You have to hard reset your mobicel ultra. Please follow the instructions below.
Turn off your mobicel ultra
Press and hold both Volume up and the Power button until it turns on.
If you come across the "No command" mode then try the following to bypass it to recovery mode:
Tap the Power key
Tap the Volume down or up
Tap the Volume down/up together with the Power key
Scroll to 'Wipe data/ factory restore' (scroll with Volume Down)
Confirm selection with the Power button
Scroll to 'Yes---delete all user data'
Again, confirm with the Power button
Wait until you see Wiping complete
Short press the Power button to 'Reboot now