Got Quoted, accepted, 3 months later Miway "we quoted wrong" and increased premium

I updated my vehicle's license plate registration on my insurance policy, only to have my premium go up by R200 and that it cant be reversed. I was told that MiWay didn't quote me correctly on the first day I opened the policy with them and have now corrected it... 3 months later, which I did not accept. Was then offered a "discount" .. which still meant the premium went up by R170 from the original quote.