ok first... you should get your guild to do it for you, not pay some other person to do it. and second if it was a one time thing it could have been anything... he may have lost his ISP connection. a scammer is someone that does it repeatedly... I have done stuff for people and lost connection in the middle before. it was not on purpose. so I am just saying... Of course I don't charge for that kind of thing, I'm more into playing the game. or playing with my guild members (friends) so I don't know what to say. there are several. threads with lists of names that are legitimate and others have had good experiences with. so there are out there. still I recommend playing through the game at least once and form a guild to help your secondaries to do such things. Or join one that does ...
to answer your question, you can do it
Here.
they want the time and date of the issue, a screenshot with district, and the names of the parties involved.
Since you were not in a district and in a instance they will also want the party leaders name. so they can look up instance logs.
however I have yet to EVER see one of these banned. maybe they get a warning sent to their e-mail, but that's about it... its a Caveat emptor situation.