Okay I got a reply from Wyoming.com and this is what it said:

P2P is allowed and works. As far as I know we don't block ports for
this reason.

Downloading illegal stuff is not just on your head. It's not
allowed. If we find out you are downloading illegal stuff you will receive
a cease and desist communication from us. If this illegal practice
continues after this communication your internet service may be
discontinued. Please, only download legal material.

So apparently, it's not my ISP. But it can't be anything else because I've checked and double checked. So what's the problem?