I would prefer to think I am one of the more well respected people on the net and people still lie to me on a regular basis. So, the oper is stuck refusing to help because he can't tell who is who. Remember this line of reasoning, its going to be coming up a lot. This one is simple. There is no way to prove that somebody is doing any of these things to you from an opers point of view.
All logs are fakable, and the oper has no way to firsthand prove it's happening.
Your best bet in this situation is to log what you can and complain loud and long to their ISPs. There's a bunch of answers to this. First, it is popular opinion at efnet that channels are not owned, and therefore, if you lose a channel, you should go make another one. But more and more you see opers killing for takeovers, so why are they helping their channels and not yours. Or worse, they could have it all set up, and some other oper could kill them halfway through because they don't like masskills and it would be all ruined.