Query still not resolved

Good day<br> <br> I have logged a customer care query about my billing at least 4/5 times now and still the query hasn't been resolved.<br> <br> My message: Reference number: E*** [#***8]<br> I did an upgrade on 10 March to a new package (MTN Choice 100) and my billing runs till the 13th of each month.<br> <br> I would assume that my March invoice billing would run from 14 Feb till 13 March 2016 and that I would be charged for my previous package (MTN Choice 50) from 14 Feb till 10 March 2016 and then the new package pro-rata (MTN Choice 100) from 11 March till 13 March.<br> <br> My March invoice however shows that I have been billed for a full month on the MTN Choice 100 package but I did not receive any benefits of this as I only got my 50 minutes, 100 sms's and 100mb of data (from my MTN Choice 50 package) for the Feb/March period.<br> <br> Can you please advise why my invoice is made out like this and I have to pay such a high amount?<br> <br> Please can someone assist me as this pathetic service is really annoying me now!!<br> <br> Regards<br> Tanja