Bad service and lying

If been trying to get hold discovery . They made an arrangement that they will only deduct R919 but last month they deducted over R2000 I have letter that if been sending them and they confirmed they will only deduct R919. So last month and this month once again they deduct over R2000 dont send me a letter and tel me you only deducting a certain amount and not do it. And I'm trying to sort out but client service never call . You they really suck and they lie .