I don’t believe Gamstop Is available in Germany, your best bet is going through your bank and having them turn off Deposits for gambling ( which I believe is available across Europe ) …Germany has just created their own gambling authority (Few months back )because of black sites and Germans using other countries gambling sites to play, so in the proposal there is meant to be safeguards for vulnerable people….But I sadly can’t read German so It might take some research from you figure out who or how they can help….but the bank is the quickest fix, good luck tho,