Mtn ******* of data bundles / day light *******

I have monitored my data bundles for a few mths now because in nov and dec 2014 data was used up within 1 wk of receiving it. On 20 February 2015 I had approx 540 mb available as per mtn x141# and on 21st I normally rec 300 plus 350 when new bundles are allocated. My 540 bundles disappeared on the 21st yet mtn has told me it gets carried over for 1 mth. On 2 occasions not all bundles were given as per the contract and On 21st February I called to ask for my 350 mb that wasn't allocated. I also spoke to Portia and queried my missing data. She promised to have a report within 3 days. I have since called twice after 21st and to date no response. I have called again today and was told I can't speak to a Manager because they busy and there response time is 24 hrs. I have been a loyal subscriber of mtn for years now and after receiving this kind of service I will not be renewing my contract. The supervisor Brenda lebeloane told me today that we are branded unfortunately I fall into medium value and maybe this is why mtn is delaying in getting back to me. Thks for branding me MTN. Have I ever missed a payment. Have I ever been late or has my debit order ever been unpaid.