Someone has Apple ID with a gmail mail that collides with mine

Something strange is happening with my Apple ID. I have an ID that is surname.name at gmail.com and the DOTs are suppressed in gmail, so emails like s.u.rname.name or surnamename are the same as mine (and I receive the emails from that address) and google doesn't let people register those emails. It seems that from yesterday someone managed to register an Apple ID like an address surmanename(at)gmail.com that collide with mine and is using that ID, nd I receive the emails that Apple is sending to this guy. I don't understand how this guy has managed to certify his email. Anyway, this is going on. Today I've received another notification of a purchase. How can I reach the apple security support to explain what's going on? They seems to have a serious breach in security without certifying emails.

Thank you to anyone who can help me.

Best

Paolo