Chimmu.co charged my ApplePay/Cash - fraudulent charge

I made the mistake of purchasing a planner app for $5.90 from chimmu.co. It tried to charge me 17.90 under the company Dip Glossy, but was declined. Then it tried charging me again under Chimmu.co for $17.90 and was declined. I thought that was the end of it. I just noticed a charge from Chimmu.co for $42.95 was successful on my ApplePay. How do I report this to Apple? How do I get my money back? How do I stop this from happening again?