Bad Customer Service

I called the contact centre (808) about a week ago to cancell my contract,they told me they are experiencing high call volumes and that someone will call me back withing 48 hours (***).No body called me back & now I cant cancel my contract and i was told to cancel my contract on the last day(13th May 2015) the date was given to me by a mtn service consultant.I had this problem before and ended up paying for an extra month.