Suppose to have first 3 months free internet, but the debit orders is going off my account.

I have signed up for a 3 month free internet promotion and started internet during October. Towards the end of November i received a bill of R1801.84 in order to pay for November and the portion used in October. I queried this with the sales agents who promised it will be sorted out. I did not receive any further feedback and then at the end of November the debit order went off my account. I then reversed the debit order and inform the sales agent Amman Rampersad of the situation and again i was promised that it will be sorted out. During this week I have spoken to an Cellc call center agent who was calling me to collect the outstanding money I then explained the situation and this person informed me that there should be a reference number to my case. I then opened a case "REF: ********** 605" and was told someone will get in touch with me with 2 working days. This was 20 December and last night 22 December the debit order was again taken from my account in 2 parts R1000 and another of R801.84 and i expect that the December invoice will follow come next week. I was informed that the first 3 months is free and will only start paying 90 days after installation. This is the way i budgeted but now i have to plead and suffer to get this sorted out with the worst service i have experienced in my life.