Failure to resolve incorrect billing

On 17 June I cancelled my contract and migrated to prepaid. My contract was only cancelled on 22 June - a process that should have take 2-48 hours. As a result, another month's fees were charged on 20 June - which I refuse to pay due to your inefficiency. I will pay the R219 for May, but not subsequent fees charged. I placed a stop payment on these MTN debit orders, been to the Claremont store 3 times, tried to get through to your customer care line on numerous occasions only to he kept on hold for 30 minutes and still not getting through, or being cut off as my cellphone is no longer recognised on your network. When I did speak to consultants, promises were made to resolve my query, but never followed through to its entirety. I logged 2 customer complaints, yet still no finality other than sms's prompting me that I am in arrears. I am an excellent paying customer in all my business dealings. Never have I ever experienced such inefficiency, frustration and bad customer service. Please get back to me ASAP.