Poor service delivery whilst paying for it all!!!

<p>I have a contract with MTN and I have a problem with my data each month, every month once I get half way through my data or atleast 60% through it, it does not allow me to use the balance although there is enough to use, upon the million calls to customer care, I was told I am still listed to have BIS, which I havent had in years, I have reference numbers from motnh to month and lose data that I canot use yet I am paying monthly for this data, I have lost a total of around 1.8gigs of data from starting the contract and they still have not resolved this issue. ..1 department says I am listed as having BIS , yet another says everything should be working as per normal and nothing is getting fixed...I am one very unhappy customer because I am paying for this monthly but I am having to buy airtime and convert it to data which is the reason I got a contract, but its catching up to me!!!!</p>