Hacked Iphone

Hi, My iphone is hacked and I am unable to reset my phone as the phone does not allow me to.

When i press on reset all settings or erase all content and settings the passcode that I enter pops up that it is wrong, but if I choose and other reset option (reset network settings, etc) and I am asked to enter the passcode it accepts and resets those settings except for the general settings.

Please advice how you can reset the phone to factory settings when it doesn't allow from the phone itself.

thanks