I was able to order an Xbox Series X from a site called spieleladen.eu, but strangely enough they only offer prepayment, which means paying first for goods. Now I ask myself how do I know that I can trust people because Iban also starts with IT. Can someone help me? Perhaps someone has already ordered there or how can you check whether they are serious people? (Thanks in advance)
No is not serious
never pay in advance
ES indicates a Spanish shop. Sending money abroad in advance would be pretty naive. Of course, there's a chance the store is reputable, but reputable stores tend to accept common payment methods as well. I wouldn't risk it if I were you.