BAD SERVICE/WRONG BILLING

These people keep overcharging me. I initially took out a Prestigio tablet the cost less than R130 per month with 300mb data. But now they adding money on it saying I have run a bill first of R630 in January, now it's R720,38. <br> I called them continously to resove the matter but the incompetency of the call centre staff is beyond my understaning. I have requested call recordings two weeks ago still I havent received anything. In January they said they will reduce my billing after my allocated data to R1 BUT now I suprisngly owe them R720 because they say I left my data running. <br> Now when I ask about thier so called bill reduction to R1 they say it's not gurranteed. <br> My question now is how do you run a bill of data of either R630 or R720 when you have a monthly contract of R130 with 300mb data allocated to you and they first said that when that allocation is finished they will soft lock the tablet until next billing month to changing the story to they will reduce the open bill to R1 so that I cannot use data after the 300mb is finished to that also not being 100 % gurranteed. <br> How may stories can one company spin on a single matter?