diff --git a/src/components/call-desk/call-widget.tsx b/src/components/call-desk/call-widget.tsx
index b3f7c4b..d95303d 100644
--- a/src/components/call-desk/call-widget.tsx
+++ b/src/components/call-desk/call-widget.tsx
@@ -92,6 +92,7 @@ export const CallWidget = () => {
         isOnHold,
         callDuration,
         answer,
+        reject,
         hangup,
         toggleMute,
         toggleHold,
@@ -171,7 +172,7 @@ export const CallWidget = () => {
                     <Button size="md" color="primary" iconLeading={Phone01} onClick={answer}>
                         Answer
                     </Button>
-                    <Button size="md" color="primary-destructive" iconLeading={PhoneX} onClick={hangup}>
+                    <Button size="md" color="primary-destructive" iconLeading={PhoneX} onClick={reject}>
                         Decline
                     </Button>
                 </div>
diff --git a/src/hooks/use-sip-phone.ts b/src/hooks/use-sip-phone.ts
index 49cda38..abc4811 100644
--- a/src/hooks/use-sip-phone.ts
+++ b/src/hooks/use-sip-phone.ts
@@ -110,6 +110,10 @@ export const useSipPhone = (config?: Partial<SIPConfig>) => {
         sipClientRef.current?.answer();
     }, []);
 
+    const reject = useCallback(() => {
+        sipClientRef.current?.reject();
+    }, []);
+
     const hangup = useCallback(() => {
         sipClientRef.current?.hangup();
     }, []);
@@ -159,6 +163,7 @@ export const useSipPhone = (config?: Partial<SIPConfig>) => {
         disconnect,
         makeCall,
         answer,
+        reject,
         hangup,
         toggleMute,
         toggleHold,
diff --git a/src/lib/sip-client.ts b/src/lib/sip-client.ts
index fe7a020..129a491 100644
--- a/src/lib/sip-client.ts
+++ b/src/lib/sip-client.ts
@@ -15,13 +15,9 @@ export class SIPClient {
     ) {}
 
     connect(): void {
-        // Enable JsSIP debug logging to diagnose connection issues
         JsSIP.debug.enable('JsSIP:*');
 
         const socket = new JsSIP.WebSocketInterface(this.config.wsServer);
-
-        // Extract SIP ID from URI for authorization_user
-        // URI format: sip:521814@blr-pub-rtc4.ozonetel.com
         const sipId = this.config.uri.replace('sip:', '').split('@')[0];
 
         const configuration: UAConfiguration = {
@@ -61,13 +57,19 @@ export class SIPClient {
 
         this.ua.on('newRTCSession', (data: RTCSessionEvent) => {
             const session = data.session;
+
+            // If we already have an active session, reject the new one
+            if (this.currentSession && this.currentSession !== session) {
+                session.terminate();
+                return;
+            }
+
             this.currentSession = session;
 
-            // Extract caller number
-            const remoteUri = session.remote_identity?.uri?.toString() ?? '';
-            const callerNumber = remoteUri.replace('sip:', '').split('@')[0] || 'Unknown';
+            // Extract caller number — try multiple SIP headers
+            const callerNumber = this.extractCallerNumber(session);
 
-            // Setup audio
+            // Setup audio for this session
             session.on('peerconnection', (e: PeerConnectionEvent) => {
                 const pc = e.peerconnection;
                 pc.ontrack = (event: RTCTrackEvent) => {
@@ -95,15 +97,13 @@ export class SIPClient {
             }) as CallListener);
 
             session.on('failed', (_e: EndEvent) => {
+                this.resetSession();
                 this.onCallStateChange('failed');
-                this.currentSession = null;
-                this.cleanupAudio();
             });
 
             session.on('ended', (_e: EndEvent) => {
+                this.resetSession();
                 this.onCallStateChange('ended');
-                this.currentSession = null;
-                this.cleanupAudio();
             });
 
             if (session.direction === 'incoming') {
@@ -158,10 +158,22 @@ export class SIPClient {
         }
     }
 
+    reject(): void {
+        if (this.currentSession && this.currentSession.direction === 'incoming') {
+            // Use 486 Busy Here for rejecting incoming calls
+            this.currentSession.terminate({
+                status_code: 486,
+                reason_phrase: 'Busy Here',
+            });
+            this.resetSession();
+            this.onCallStateChange('ended');
+        }
+    }
+
     hangup(): void {
         if (this.currentSession) {
             this.currentSession.terminate();
-            this.currentSession = null;
+            this.resetSession();
         }
     }
 
@@ -197,6 +209,11 @@ export class SIPClient {
         return this.ua?.isRegistered() ?? false;
     }
 
+    private resetSession(): void {
+        this.currentSession = null;
+        this.cleanupAudio();
+    }
+
     private cleanupAudio(): void {
         if (this.audioElement) {
             this.audioElement.srcObject = null;
@@ -205,6 +222,45 @@ export class SIPClient {
         }
     }
 
+    private extractCallerNumber(session: RTCSession): string {
+        // Try P-Asserted-Identity header first (most reliable for real caller ID)
+        try {
+            const request = session.direction === 'incoming' ? (session as any)._request : null;
+            if (request) {
+                // Check P-Asserted-Identity
+                const pai = request.getHeader('P-Asserted-Identity');
+                if (pai) {
+                    const match = pai.match(/sip:(\+?\d+)@/);
+                    if (match) return match[1];
+                }
+
+                // Check Remote-Party-ID
+                const rpid = request.getHeader('Remote-Party-ID');
+                if (rpid) {
+                    const match = rpid.match(/sip:(\+?\d+)@/);
+                    if (match) return match[1];
+                }
+
+                // Check X-Original-CallerID (custom header some PBX systems use)
+                const xCid = request.getHeader('X-Original-CallerID');
+                if (xCid) return xCid;
+
+                // Check From header display name (sometimes contains the real number)
+                const fromDisplay = request.from?.display_name;
+                if (fromDisplay && /^\+?\d{7,}$/.test(fromDisplay)) {
+                    return fromDisplay;
+                }
+            }
+        } catch (e) {
+            console.warn('Error extracting caller ID from SIP headers:', e);
+        }
+
+        // Fallback to remote_identity URI
+        const remoteUri = session.remote_identity?.uri?.toString() ?? '';
+        const number = remoteUri.replace('sip:', '').split('@')[0] || 'Unknown';
+        return number;
+    }
+
     private parseStunServers(stunConfig: string): RTCIceServer[] {
         const servers: RTCIceServer[] = [];
         const lines = stunConfig.split('\n').filter((line) => line.trim());