unacceptable billing and no resolve of queries

I signed a contract in March with Telkom for a 20/20G LTE services the contract state R449 including the LTE modem device. Telkom then charge me for the device and I tried for 3 months to short out my billing with no joy. After 3 months I want to upgrade to 30/30G and start a new contract, then I was told there was a change to my contract and I must weight another 3 months to upgrade. I asked Telkom what the cost will be to cancel my contract they said they will come back to me. A few days past then a lady phoned me and asked why I want to cancel I told her and she said she will upgrade me and my billing will be corrected. I agree and there I made a mistake to do so. My billing is now a bigger mess I phoned Telkom and they said I must pay R2200 next month because I have two devices. I told them I battle know for months to short out my billing. I also told them why would I have two modems as I only have one sim card they said they will look into it I was wrong billed them. I phoned them again and asked if they rectify my bill I have to explain again the hole story I asked to speak with the highest authority they give me an email address that's not working. Telkom stole money from there customers and do not give a dam about them, I stopped my debit order with my bank and notify them I will only pay R549/month for a 30/30G as per contract. The next day I good not go on the internet as my 30/30G was depleted know I asked myself did Telkom be rude to take my DATA or what because there is no way a could use all my data. I bye 2G data online on the Sunday evening and Monday morning had nothing did Telkom took it. Telkom my next step will definitely to cancel my contract if you not responding in this week.. Wake up you loosing customers as you have unqualified people that work for you and they cannot resolved issues they just make a bigger mess of it.