Upgrade after annual payment disaster

I had DSTV compact plus installed as from 1 April and also made the full annual payment of R5709. On 11 August I decided to upgrade my package using the self-help options and then pay in the difference. I naively thought this would be a simple process as I was being encouraged to upgrade to premium on practically all of the communications, adverti*****ts etc from multichoice. The moment I clicked to confirm my signal was cut and my account was reflected as being in arrears. Obviously this is not possible as I had only used 4 months and 11 days out of the 12 months of the sub I had payed, yet my account seemed to have experienced a total reset to zero at this point and also somehow reverted to monthly billing. I managed to have my service restored on 12 August after calling the call center. My calculation is as follows and most call center agents have come to the same result: Initial credit of R5709 which was payed on 1 April 4 Months usage at R519 pm= R2076 11 days of usage for Aug, calculated on 30 days= R190.30 19 Days of Premium (12-30 August)= R512.67 Total usage then= R2778.67 * All pro-rata calculations done assuming 30 days per month on advice from all Multichoice employees I have been in contact with. R5709-R2778.67= R2930.33

I have also had to make further payment of R190 on advice from one of the call center agents in order to keep my subscription on: R2930.33+R190= R3120.33 total credit

Since 12 August I have spent approximately 4 hours on the phone to the call center and a further hour in a walk-in service center and am still struggling to have this problem fixed. All of Multichoice staff have given up on fixing this problem. My calls have been escalated 7 times with no feedback. The walk-in center agent promised to get back to me in 2 days and this has also not happened. I have also repeatedly asked to be put in contact with a team leader or someone in management to no avail. My account is showing that I have to pay R907 on 29 August, this amount changes every time one of the agents fiddles with my account. Extreme frustration is understating the amount of negative opinion I have towards Multichoice and DSTV at the moment. My guess is that something about my payment being annual broke the accounting system when an upgrade was requested. I have asked if it would not be possible to simply retroactively revert my entire account to monthly and just allow me to make future payments on a monthly basis. This should be a simple thing to do as the costing for past usage is identical for both scenarios. I thought an annual payment was going to simplify my admin but am regretting this to the extreme now!