Frustrated!!!

I am really frustrated by the service received by Vodacom. I cancelled my contract last year when it came to an end. I was unaware of a small amount outstanding due to no communication received about this amount. I went to get vehicle finance and was rejected due to bad credit record from Vodacom. I then called in yesterday to find out and was told I owe an amount of 289 I then made the payment to settle this. I called into the call center 3 times to request a settlement letter that I need urgently and was promised this on every call. When I follow up the process was not even done as promised and still shows my account on current and not settled. I need this settlement letter urgently. Please assist me as this is an urgent matter and I am not coming right with the call center. Thank you