You can lock your account immediately with the EMERGENCY LOCK feature in SETTING.
On the app version
Step 1: Click on your Profile icon -> Settings
Step 2: Go to Emergency Lock
Scroll down and click on the Emergency lock at Security and click “Emergency lock" -> choose the reason you want to deactivate your account as below
Step 3: Choose the reason for locking
Step 4: Select “LOCK MY ACCOUNT” and confirm again
Your account will be deactivated.
Note: You can contact support to reactivate your account later.