Why am I being charged 15$ every month when I’m not subscribed to anything ?

This forum is just a user to user forum, no-one here has any account access, try using the steps they provide on this link to find out what that payment was for.

https://support.microsoft.com/en-us/account-billing/microsoft-tan-faturalama-%C3%BCcretini-ara%C5%9Ft%C4%B1rma-398c5328-364c-d5e4-ea8f-f5ad60562a93

Then use the steps they provide on this link to cancel whatever that payment was for and get a refund.

https://support.microsoft.com/en-us/account-billing/microsoft-aboneli%C4%9Finden-nas%C4%B1l-para-iadesi-al%C4%B1n%C4%B1r-67dca30b-b323-44d5-acc2-e02f9902c472