"(Why should I fix it if they'll do it free?)"
Even though it may be intended as rhetorical, I do have an answer you should consider very seriously for that question:
If the work they do is good work, then take it there. From what I've seen in the field, though, they do well enough to fool a technically-challenged customer into thinking the job is done well when it really isn't. In the cases I've cited, they didn't put in security on anyone's wireless network and that, my friend, could be the cause of a literal life changing experience.
If you don't know enough to go behind them and know for sure that they have actually done all they should (And, if you did, why would you use them in the first place?), you could wake up one morning to a ruined life, finding you supposedly own cars, houses and land you didn't buy and now the financiers want their money and the payments are late.
Fighting this kind of nightmare can easily become a literal full-time job that occupies your waking hours with the real work of dealing with it and occupy your sleeping hours with literal nightmares. Other than the premature death of an immediate family member, I cannot imagine anything that could impact a family more.
So, my friend, do you really know that they are doing something for you--or are they really doing it to you, instead?
The only work I would trust them with is warranty work where they are simply going to handle the shipping back to the manufacturer for me.
These people aren't simply incompetent; they are potentially very dangerous.