Does the company he works for know he does this side work? Most contractors have a problem with that and for good reason. As you demostrated yourself you remember the name of the company he works for but not his name. If something goes wrong it is the company you remember even if they had nothing to do with it. You may be setting yourself up for problems if you hire the guy without the contractor's knowledge. I've had it happen several times and end up in the middle of it to save my reputation, even though I had nothing to do with the job. I've occassionally given the ok for one of my guys to do work and directly deal with Customer's but even that has come back to bite me more than once.
If you have a problem with this guy you have next to no legal recourse and the contractor is not obligated to help you. It's best to deal with a known entity, i.e. established business, who has something to lose.
Todd's Home Services
San Antonio, TX