MTN contracts worth nothing

I signed a 36 month data share contract with MTN, for almost 1 year it work very well, In my business I make use of trackers, scanners and cellphoe using a lot of data, the contract MTN offered me was my answer, 100GIG I can share between 20 cell numbers. The begining of this year it fel away, no more 20 shares but only 5, I'm in a business and use 15 to 20, so 5 does not help me, I went and asked them is a contract not supersedes any changes if both parties dont sign a contract, I got the Ombudsan involved and still 4 months later I still dont have a answer or givin a solution and worse I cant even cancel the contract from my side.