Account dispute

I took a contract with Telkom, and they said I can downgrade or upgrade after 3 months . Three months later I downgraded my contract. That is where the problems started . I went to Telkom shop they gave me the number to call. My new contract was R199. They deducted R1200 which I reversed. The following month I called they said I must pay R600 cash , which I did and they said they will deduct R254 going forward. The following month they deducted R 1 150 which they said they over deducted, they told me they overdrawn my account by R270. I asked them to put the R270 in my account it never happened. I would like cancel the contract because of uncer*****y of debit order. Now they blocked the account, I don't have data but the money was taken. I have called the call center numerous times I have alot of service numbers but they never resolve anything. They have even went as fare as dropping the phone in my ear! I would really love to cancel this service as the customer support I'd none existing!

Please help me!