diff --git a/app/models/user.py b/app/models/user.py
index e549079..e693537 100644
--- a/app/models/user.py
+++ b/app/models/user.py
@@ -22,12 +22,12 @@ class UserInDB(BaseModel):
     is_active: bool = True
     created_at: datetime = datetime.utcnow()
     code: Optional[str] = None
-    telegram_chat_id: Optional[int] = None
     telegram_user_id: Optional[int] = None
     telegram_username: Optional[str] = None
     is_verified: bool = False
     code_expires_at: Optional[datetime] = None
     is_admin: bool = False
+    expires_at: Optional[datetime] = None
 class Session(BaseModel):
     access_token: str
     client_token: str
@@ -37,4 +37,5 @@ class Session(BaseModel):
 class VerifyCode(BaseModel):
     username: str
     code: str
-    telegram_chat_id: int
+    telegram_user_id: int
+    telegram_username: Optional[str] = None
\ No newline at end of file
diff --git a/app/services/auth.py b/app/services/auth.py
index 42f2c9e..09fec0d 100644
--- a/app/services/auth.py
+++ b/app/services/auth.py
@@ -43,6 +43,7 @@ class AuthService:
             is_verified=False,
             code=None,
             code_expires_at=None,
+            expires_at=datetime.utcnow() + timedelta(hours=1),
             is_admin=False
         )
         await users_collection.insert_one(new_user.dict())
@@ -62,7 +63,6 @@ class AuthService:
         self,
         username: str,
         code: str,
-        telegram_chat_id: int,
         telegram_user_id: int | None = None,
         telegram_username: str | None = None,
         ):
@@ -73,15 +73,26 @@ class AuthService:
         if user["is_verified"]:
             raise HTTPException(400, "User already verified")
 
-        if user.get("telegram_chat_id") and user["telegram_chat_id"] != telegram_chat_id:
+        if user.get("telegram_user_id") and user["telegram_user_id"] != telegram_user_id:
             raise HTTPException(403, "This account is linked to another Telegram")
 
         if user.get("code") != code:
             raise HTTPException(400, "Invalid code")
         
+        if telegram_user_id is not None:
+            existing = await users_collection.find_one({
+                "telegram_user_id": telegram_user_id,
+                "username": {"$ne": username},
+            })
+            if existing:
+                raise HTTPException(
+                    status_code=403,
+                    detail="This Telegram account is already linked to another user",
+                )
+        
         update = {
             "is_verified": True,
-            "telegram_chat_id": telegram_chat_id,
+            "telegram_user_id": telegram_user_id,
             "code": None,
         }
         if telegram_user_id is not None:
@@ -89,7 +100,10 @@ class AuthService:
         if telegram_username is not None:
             update["telegram_username"] = telegram_username
 
-        await users_collection.update_one({"username": username}, {"$set": update})
+        await users_collection.update_one(
+            {"username": username},
+            {"$set": update, "$unset": {"expires_at": ""}},
+        )
         return {"status": "success"}
     
     async def get_verification_status(self, username: str):
diff --git a/main.py b/main.py
index 9fc1b17..13e4ea1 100644
--- a/main.py
+++ b/main.py
@@ -8,6 +8,7 @@ from fastapi.middleware.cors import CORSMiddleware
 
 from app.core.config import CAPES_DIR, CAPES_STORE_DIR, SKINS_DIR
 from app.webhooks import telegram
+from app.db.database import users_collection
 
 app = FastAPI()
 
@@ -21,6 +22,10 @@ WEBHOOK_SECRET = os.getenv("TELEGRAM_WEBHOOK_SECRET", "")
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     # ===== STARTUP =====
+    
+    await users_collection.create_index("expires_at", expireAfterSeconds=0)
+    await users_collection.create_index("telegram_user_id", unique=True, sparse=True)
+    
     if BOT_TOKEN and PUBLIC_WEBHOOK_URL:
         payload = {"url": PUBLIC_WEBHOOK_URL}
         if WEBHOOK_SECRET: