When the front office doesn't work well with you, the medical biller

It's a tough call to know exactly WHEN to resign an account.
I had an account recently that was an absolute disaster.
They never checked eligility, they didn't track copayments or other important patient information, the billing always came late, I never received copies of EOB's in a timely fashion, and they were at least two months behind in MY invoices month after month.
This situation is clearly NOT ideal and was quite painful for me, as a small business owner.
So, I made the difficult decision of offering my notice of termination.
Has this type of situation happened to you?
I'd love to hear more and how you handled yourself.