I'm so sorry that you are having a difficult time, Thom. You need to remember that everyone has problems like you are currently having from time to time.
1. Keep up the communication with the office manager at your doctor's office. You are working to pay your outstanding balance and that's the important thing. I'm sure they will be understanding toward your financial situation, especially in this economic environment. Be prepared to pay in advance from now on, though.
2. You gained weight b/c your band slipped. You were heavier before being banded, lost weight when your band was properly inflated, and gained weight back since the problems. You should lose weight again once your back to that "sweet spot". Your doctor just wants you to be healthy, and I'm sure that he understands it's difficult for you - if he didn't, he wouldn't be this type of surgeon. Since this doctor knows your history, I would stick with him. You shouldn't let this finanical issue block your effort of being healthy. So what if he's cranky. You just need his surgical skill. The 30 minutes you'll spend talking to him pre/post-surgery is nothing in the overall scheme of things.
Good luck to you!