Data Service not being restored

I have made an arrangement wit Cell C to limit my Data usage to only R150 a month. (this includes my 2 gig bundle). Every month so far they have assisted me in this matter and stops the account on the agreed upon amount. I was also able to load extra data before the account was stopped onto this data line. On 2015/08/14 I bought additional data as I have always done, but it did not reflect on my line. I phoned customer services, who then informed me that it is impossible to load prepaid data on the line, although I had been doing this for more than a year. Ok, so where is the money that I paid for the top up data, as the line number was specified when I bought it? If I can't load data anymore, since the contract has obviously been amended without my knowledge, should it not be allocated to my account? Next, I also have the problem that my line is never re-activated after they receive their payment. Every month it is the same problem. I have to phone and beg for my line to be activated every month. The line has been off since 2015/08/31. I bought a bundle before it was locked, and have paid every month. so what is the problem?