MTN ****mers

I'm very upset with MTN. I was under the the impression that my contract would end March, so I called them in February on the 16th and they said I should call on 16th March on the day the contract would end, I called on the 16th March they said they can't help me because I didn't do the cancellation a month in advance but I had called in Feb, OK so then I was told to pay first then cancel. Payment was made on the 25th March and I called on the 28th and spoke to Mbali and she said cancellation takes 30 days then she gave a Ref *** and said I need to pay in April which would be my last and now all of a sudden I got an email to pay another addition R527 on the 8th May. I feel ****med and they just won't cancel my contract MTN are ****mers