How can apple help if a partner has your apple password and has changed it so you cannot access your devices

If you are the original owner, contact Apple. Apple can remove the ID  if provided the required paperwork to include the original purchase receipt with the serial number on it. 

Request additional support for unlocking your device.    -

You used to be able to take the device, the original purchase receipt with the serial number, and a photo ID to the nearest Apple Store (if it has reopened) and have them remove the ID. This may have changed, so call the store before going to make sure they can help.

Genius Bar Reservation and Apple Support Options - Apple.   -

See the following from If you think your Apple ID has been compromised - Apple Support

If you completed the steps above and think your account might still be compromised, contact Apple Support.