Turn on airplane mode
Disconnect from Wi-Fi and Bluetooth
Restart the phone in safe mode
Delete suspicious apps
Remove recently installed apps you do not trust
Clear browser history, cache, and downloads
Check app permissions and revoke suspicious access
Update the operating system
Update all apps
Run a trusted mobile security scan
Change passwords for important accounts from a different device
Enable two-factor authentication
Back up important data
Factory reset the phone if problems continue
Restore only essential data after resetting
Contact your phone manufacturer or carrier if needed