Why on earth is this person not sweeping nightly into their business bank account? Never leave money in your processor account... they are not your bank!

This is the same stuff people complain about with PayPal - failing to realize this scenario (to this extent where it's threatening your business) is almost entirely the business operator's fault due to a severe lack of understanding of how to use a processor.

My guess is this person's processor account went from small benign numbers and then suddenly had a surge of business (possibly seasonal). This sudden increase in volume can (and will) trigger anti-fraud audits from your processor if you do not already have a well established history with them. You go through it, and move on. Generally it's not an issue if you sweep nightly!

Spread the word - your payment processor is not your bank. Sweep nightly, it's almost always a free service they offer.