I have been over billed

I am a former customer of Nashua mobile transferred to MTN. In December, i upgraded my phone and brought a second phone. I was told that my monthly bill will be R1000,00 and they charge me R1200.00, which include handset fee . I phoned MTN to query about this they informed me that they were going to listen to the recording of the upgrade because the upgrade was done over the phone. I called them again to find out what is the outcome after they listened to the recordings. They are telling me that they will not listen to them, because its was not their duty to tell me about the additional cost, Nashua was suppose to tell me. The person from the contact center was talking with attitude telling me that I am not the only person with this issue, meaning the is nothing special about and I must just take what she is telling me. The reference number is ***.<br> <br> The second issue they were charging me BIS while my phone was not compatible to the service. I have been requesting them to cancel this for some time. Today they told me that it is cancelled and R51.74 was refunded to me, however i was charged R60 every month, and i don't know for how long. Reference number is ***.