I "hired" ACCOUNTSRECEIVABLE.COM 2 months ago to collect on a very simple and well documented debt. They send the debtor a few letters and made a few phone calls, but then as soon as the debtor said he wasn't going to pay, they basically dropped the case and didn't do anything except waste 2 months of my time. They didn't take any actual legal actions as they claim they will... they basically just look for the really low-hanging-fruit and only send threatening letters to people easily intimidated.
Never use this company, they are not a real collections company at all.