On your APPLE electronic receipt you will see an invitation to ‘Report a problem’. Report what you say here as your problem and Apple will contact you.
If for some reason you do not have a receipt, follow the instructions in this Apple document where a similar ‘Report a problem’ link is offered. https://support.apple.com/en-gb/ht204084
Where subscriptions are concerned, you should try to spend a few moments reviewing this document which explains how you can view, change or cancel them. https://support.apple.com/en-gb/HT202039
One other check you can make. If you’re seeing an unfamiliar charge on your bank or credit card statement, read through this document for guidance. https://support.apple.com/en-gb/ht201382