[seningen]

Good will point #1:
If I were them -- I would waive the previous repair costs -- as that
did not resolve the problem.

I would then look to fix it correctly -- and only charge for what fixes the problem.

Good Will point #2:
I'd throw you a bone for having to deal with the issue more than once.

I think it is fair to pay for the proper fix -- but you shouldn't pay for any
fix that was incorrectly diagnosed.

Mike