I'd avoid PA. If anything happens and even if you get their insurance or whatnot, you'll either 1. Not get anything in compensation and no punishment will be given out to the seller 2. Hassle them for a few months and you may get some sort of compensation.
I purchased something awhile back (an account for a different game) and although I had all the proof (including the seller admitting it), it took about 3 months to get a refund with me constantly messaging them about it.
Personally, I'd go with Sythe or Osbot although I may be a bit biased. Just make sure they're very very reputable esp for a main account.