2 month long nightmare

In the second week of August 2017, I did an online upgrade to a Samsung S7. The got the phone very quickly but soon realised the phone was faulty as immediately the phone would heat up when charging it and the battery would run down in a couple of hours. I contacted Vodacom to have the phone returned and they advised it would be collected the following week. It took another call, but on 23 August I was told to email ********** at Lennon sent me an email with a ticket number and told me the phone would be collected. On t28 August I emailed Lennon again to advise him that RAM had not yet contacted me and he told me to contact them myself. I phoned the number he gave me and was told they would get back to me. On 30 August I emailed Lennon again, but got no response. Eventually in the 1st week of September RAM collected the phone After a week I checked my online account, and the phone was still showing on my records, so I called and spoke to an agent who promised me it would be resolved in 3 working days and gave me my first reference number 1 - ********** ********** . I waited another week and then checked on online account and there was still no change. I have called a few times and spoken to various agents and someone has even called me after I responded to the SMS saying my issue had not be resolved, but nothing has changed. I called last Thursday, 5 October again, and the agent advised that the phone had been returned, she apologised for the mix up and promised it would be resolved by the weekend. That reference number was 1 - ********** ********** . I thanked her, and paid my account which was R5***** on both the website and the invoice I received. On Sunday, 8 Oct I received an SMS stating that I had short paid my account. On Monday, 9th October I received an SMS thanking me for paying my account, yet when I log on today, it shows that my account is in arrears of R195. It is also showing me that my October account is R7032.09 as you are charging me R6520.80 for Equipment - Balance of Contract!!! For what phone? The one I sent back to you as it did not work? I am at my wits end and do not know what to do. How can you provide service like this and who can I go to for help?