diff --git a/src/lib/services/spotify.ts b/src/lib/services/spotify.ts
index 92c4912..8a0a2a7 100644
--- a/src/lib/services/spotify.ts
+++ b/src/lib/services/spotify.ts
@@ -185,13 +185,13 @@ export class SpotifyAPI {
     this.expiresAt = Date.now() + (data.expires_in * 1000);
 
     // Note: Spotify may or may not return a new refresh token
-    const refreshToken = data.refresh_token || this.refreshToken;
+    const refreshToken = data.refresh_token || this.refreshToken!;
     if (data.refresh_token) {
       this.refreshToken = data.refresh_token;
     }
 
     // Save refreshed tokens to store
-    await saveTokens(this.accessToken, refreshToken, data.expires_in);
+    await saveTokens(this.accessToken!, refreshToken, data.expires_in);
 
     return {
       access_token: data.access_token,