I have got a Activation Lock on my iPhone and I need to get it activated. I don't know what Apple ID I was using with my iPhone. It shows as U***@h******.uk which is too short to be my email address. I have reset all my Apple ID passwords and none are act

I have got a Activation Lock on my iPhone and I need to get it activated. I don't know what Apple ID I was using with my iPhone. It shows as U***@h******.uk which is too short to be my email address. I have reset all my Apple ID passwords and none are activating my iPhone. I have also been into the apple store and they have tried to find out the Apple ID my iPhone was using but this was not successful. The serial number of my iPhone is: C32JN641DTWF