MTN South Africa data contract issues

I hate to say this but MTN is not taking their clients serious,i have MTN data contract that i took with Mondo the contract was R259 but i am paying R400 and its been 3 months now and the funny part is i am only using a data that i am given not extra ,when i call Mondo they are telling me alot of nonsense about subscriptions that are not there,so please fix this problem i won't pay R400 for mtn 80 GB ill rather Go to Vodacom or other network provider ,i was asked at MTN Store why did i took a contract with Mondo i should have went to MTN store myself, but you allow Mondo to sell your product so fix this nonsense people or i will cancel this sh**t Data deal.