What should I do about my ex owing me money?

I am a complete idiot because I somehow overlooked my statements for a few months and didn’t realize these charges that haven’t been made by me. I realized that when me and my ex were together I let him use my card to buy a video game on XBOX Live.

Anyways, a few months ago as stupid as I am I recently noticed $10—$30 charges made monthly to my card. I called him and he said that it couldn’t have happened, but then he said it was true and he didn’t know it billed my card so he called the company to cancel.

I noticed again that it charged me again, and my ex said he’d take care of it. He then was open to communication with me about payments to me for what is owed…that was until he got a new girlfriend. She hated our communication even though it was business and he just blocked my calls, ignored my texts, and ignored me completely as if I never existed.

At first I was very hurt that us on good terms was gone…but then I got even angrier and I dont’ give a f*** about it anymore. He hasn’t been returning my messages about the money that is owed AND the card was charged again!

I can’t believe after 5 years of being there for him I was getting this treatment! What the heck?! I feel like a complete idiot betrayed. I’m changing my card first thing, but I don’t know what to do about him. I am beginning to grow a hatred for him because of this.
All because his gf is jealous he stops ALL communication and stops paying me? UGH!