Vodacom is overcharging me

In December i had a credit of R5000 with Vodacom and i requested it to be payed back to me and that took about a month or so to be through. It was paid back to me in March and by that time it was about R3000 due to that fact that they debited the monthly subscriptions. Now, in April, they charged me R1354 instead of R600(+) which is my monthly subscription. When i enquired about the overcharge, the consultants said i did not pay for January. This accusation of not having paid is very odd to someone who had a credit of R5000 at the time. <br> <br> The sad part is that the consultants who tried to help me in this regards proved to be useless as they could not explain why my account was not payed in Jan whereas i had a credit of R5000.<br> <br> I am struggling all the time with the inconsistency of vodacom billing and i cannot wait to pay up my account and leave vodacom alone with its poor service