Problem with store

Hello

I have a problem with the store and the subscriptions in it. For three months now, I have been receiving an SMS every week for something I bought worth BGN 6.48. I dare say that there is no such thing on my part. For three months in a row, my phone bill is BGN 26 more because of something I don't even know what it is! Could you please explain to me? who will return my money?