Rediculous data account - No assistance

My data ran out unexplicably in December 16 without any reason. Received a data account for R 8000. This all started 11 Dec 2015. I logged a query. The call center agent confirmed they will not debit my account with this amount before the query is not resolved. I made calls to them, 2 Jan, 6 Jan, 7 Jan, 20 Jan, 29 Jan i held for 45, 32, and 16 minutes after giving up. They went straight ahead and debited my account while with every call they confirmed that my \service request\" was still in the queue. I reversed the payment at the bank. 3 Feb i spoke to Thaphelo (manager) who confirmed there was supposed to be a credit of R 7500. I asked him to confirm this by mail. Never received the mail. 6, 7, 8 Feb and every other day i receive automated voice calls from vodacom requesting payment. called again 8 Feb, Spoke to Zolia at the advanced data center. she would sort it out and call me back. never heard from her again. went to Vodacom's website and sent an email from there on 15 Feb. no response. I have references for each call mad next thing that will happen is that my credit record is affected and they cut me off. This is my last resort to get some kind of assistance"