Has anybody found a reliable way to get in bad debts?

My business turnover is about R1.2m per year, yet my debtors book is just over R1m. I prescribe to Accountability and have used an attorney. All with basically zero results. As I understand I cannot take them to small claims court (as a business) Problem wit suing them is that it costs me legal fees to sue (which I know I can add to their account) and then they agree to pay R250 per month. Two months down the line they stop paying again (not even covering the legal costs yet) and I have to take them to court again...

Please can somebody point me in the right direction?