Promo from upgrade now being billed for incorrectly

I am desperately trying to get incorrect billing sorted out on my account. I spoke to a consultant about a month ago and was advised a credit will be sorted out in respect to being charged for a promotion I got with my phone upgrade. Vodacom sms'd to say it would be charged, I called them and said no it was a promo and I do not wish to keep on with that. I was advised to ignore the sms as it wasn't going to be billed for. Then I got my last statement and there it was billed for. I called Customer Care and the lady submitted the request to credit my account. Now I am being pestered by Vodacom because my account is in arrears by R140. I again call and get told to phone 082135 as *** can't help me. I do that and it redirects me to the same department that told me they can't help me. I have been holding on for ages and I do not have time to wait on the phone all day long. I am absolutely sick and tired of this nonsense. Will some one please contact me so that this account can be rectified asap as I am not going to pay for this extra billing when I have from the start communicated with Vodacom about this.