Telkom overcharging me

I app**** for the January deal at Telkom for uncapped wifi which was supposed to be R807 and I got the deal. From the first month, Telkom charged R1200+ and I thought that it was pro-rata charges or something so I didn't mind. The second month came to Telkom charged me R1200+ again I called the call center and they told me everything was okay on their side so I thought maybe it must be a mistake. Four months of Telkom overcharging for a contract that was supposed to be 807. To date, I have been overcharged more than R3800 by Telkom. I went to the store and opened a dispute and the consultant saw that my contract was wrong so she opened a dispute so I can be credited with my money but later that day someone called me a told me that my account can not be credited because I benefited from the incorrect contract. 9 months Telkom has been taking my money now I am supposed to be happy that I was given a wrong contact. I went back to the store again to get this sorted and I am still waiting for the contract to be changed to the correct one and the money I am owed to be credited to my account. I am very disappointed with Telkom they are a huge company to be *****ing money from their users.