Erroneously blacklisted phone still not sorted

I had changed the account that vodacom debits for my contract in April this year. In May they debited the old account instead of the new and I was told my account was on arrears. All that sorted, they double debited for May and all was fine. Suddenly in July my phone stops working and I'm told it's blacklisted for bad debt!!! All payments have gone through, I've spoken to more than 5 different people at customer care, gone physically to the vodacare store and everyone promises that it will be sorted in 48 hours to no avail. I'm at my wits end and it is of such great inconvenience as I can't make or receive calls for the past month which has also affected my business. After visiting vodacare after 3 weeks of no joy, the phone was unblacklisted and worked for about 6 hours the next day but now back to being unable to use the phone . Do not know what to do now, will probably change to another service provider as I'm sick and tired.