I worked with one for a period of several months, a few years ago. Initially (for at least a few months if not a full year), they're not doing much that you can't do yourself. Just sending a note to each credit bureau denying existence of anything that looks bad, and disputing any late payments, and the like. Seeing what sticks.
For the monthly fee (I think it was like 79/month maybe?) I can't recommend it as being a worthwhile investment. At the time, I too, had been referred by a loan officer.
In hindsight, the fact that a "loan officer" was referring me to a "credit repair" service really should have been my first clue. From what I have gathered, there's really only one company that is well known for this service, so it may even be the same one.
In the strictest sense of the word, _nobody_ can get accurate information removed from your credit report. However, sometimes you get lucky in cases where the creditor doesn't repond to the verification request or the like. That's basically what a repair company banks on... that, and some pseudo-legal bullying tactics in the dispute process.
So, that's my .02.