If the account receivables are for services rendered then I am not too concerned because as has been pointed out the default rate should be manageable. What concerns me is was business being booked as longer contracts were signed but all the services not yet delivered? In other words was a 6 month contract booked as revenue immediately even though the client hadn't received all of the services. The client may then have cancelled the balance of the contract which means a hit to AR's and a restatement of revenues and earnings.
Management is keeping us in the dark far to long.
On the positive side I do think they have a business model that will work, I think I read something like 28,000 wells will need fracking in 2013 in the USA alone. The fact that the CFO was only demoted and not fired indicates that there probably was nothing more serious than incompetence involved. Not good but probably also not a company killer.