Please confirm!

The data contract on my account is expiring on 15 May 2015. I don't want to renew/upgrade and called Customer Care on 15 April 2015 to give 30 days notice of cancellation as per contract. I did not receive a ref no and was told to call again the next week to confirm. I called again on 23 April 2015 but could not get a very clear answer. I then contacted MTN online to try and get confirmation and got the ref no ***. No answer yet. If MTN does not cancel this contract on 15 April 2015 (which I don't even use because I get NO signal) I am going to be EXTREMELY upset! I cancelled a previous data contract a few months ago with one phone call and I can't understand what the problem is this time!