Paying for services not rendered.Dissatisfied

Almost 3yrs ago I took a contract out with mtn on a sim for which I pay R200 pm.For the.last year iv been trying to cancel this contract and they adamant I can't.I lost my sim card when my phone was ****** which I reported to them.And tried canceling the contract I.was told to get a new sim would cost me R250 now would I.want to.do that when vodacom sim stop is free and I can buy a sim card for R2.Thats just a no brainer.I was also told besides paying R200pm if I.want to cancel the contract I must pay R200 additionally.Which is totally a *******.4 the last year they have been taking R200 every month.A service not provided.Total *******.I was told that's how business work.Can I possibly get a solution to this evil ******ion,or be pointed in the right direction please.