iPhone is locked with Activation Lock by scammers

You are going to need a receipt that shows the phone's serial number to prove you were the one who purchased it. From where did you purchase that iPhone? If you purchased it from an Apple Store, try getting a copy of your receipt here:

https://contactretail.apple.com/Solutions

Otherwise, if you paid by credit card, see if your card company can provide a receipt. Good luck. Sorry this happened to you.

I'm afraid, the official Apple Support will need more proof of ownership to be able to help you.

Have a look at the related article:

Additional Support - Activation Lock - Apple Support

Im sorry but we can't help you...

You need to prove that you are the owner of the iPhone.

And how did it happen?