What are they in relation to me?

What is my mom’s cousin’s (Billy) daughter to me? Her last name is a common Filipino last name…

I was visiting the country and someone hit on me and then later I found out he had the same last name as my mom’s cousin’s daughter. So that’s gross O.o I told him we are some how related and he said in his language “what a waste..” Her dad is his uncle. Her dad is my 1st cousin removed i think.