Vodacom are holding onto my money!!!

After an issue that has been going on since March 2017, I eventually found out that Vodacom would refund me about R2000.00. When my November debit order did not go off my account (after I phoned to confirm it would), the customer care consultant said that an amount of R504 had been taken off the credit on my account. I had specifically asked Vodacom to REFUND me, not CREDIT my account. I eventually managed to get hold of someone (after having my call dropped 3 times, at my expense) and after about 30 minutes on the phone and explanations going back wards and forwards, she said that she would confirm that the refund would take place. I then received a refund of about R1200. So what has happened to the other R800? Vodacom apparently has a "Solutions" department, but I'm afraid the solutions only seem to suit them. Vodacom have also billed me for a device that was cancelled in October. I am also ready to cancel my other Vodacom device as we no longer have internet access. Please Vodacom, sort this out!