MTN WORST MISTAKE EVER!!!

I was paying for a contract with them.. 24 months fully paid never missed a payment. When I told them I want to cancel in July they said I should have notified them 60 days before of which they have never told me. I have been sending them countless emails and messages on Facebook since they blocked my number for calls. Right now, they said I owe them a lot of money that I don't know. MTN is pathetic to the core!