Short story short:
I was supposed to send btc to an adress, I copied+pasted the address and sent the amount. Later the guy tells me he didn't get it. I checked where it was sent and it was an complete different adress. So when I copy+pasted btc addresses it changed into the same one each time. This is called clipboard btc hack or something like that. I just want people to be aware and not loose your btc double check!