Worst service ive ever had

I took out a cell phone contract with cell c in February 2015, in May 2015 i took out another contract with them (both being top ups) I was told that the pro rata will be debited the end of June. End of May they Debited R158 which is none of my monthly installments. They Did not deduct the Cellphone contract which was supposed to be R353. I Phone in telling them they hadn't deducted. Got told i would get a response in 2 days. , a week later nothing. We call in again same thing is told. 2 days time.i called into the call center on the 22nd of June got told that they don't have a answer for me ( note this has been over a month now) not one person has called me back. When i go into the cell c store yesterday i get told the R158 is for my top up contract which makes no sense i have been paying R353 since February. They now want to bill me R867 the end of June for what!!!! i haven't received one statement for my First contract either. I got told i cant cancel my debit order without a valid reason, my reasoning is that cell c is not capable to deal with my finances. I don't want them to debit when ever they feel like it an what ever amount they want.