Battling to get the contract termination fees

My monthly subscription was suddenly increased without my consent and approval by MTN. I then phoned MTN on Thursday morning and asked that my contract which is about to expire in a month's time be terminated and converted to prepaid. I was told that I will get an e-mail from the Retentions department within 48 hours confirming the termination fees and all the procedures to follow. Its been 5 days now and I'm still awaiting an e-mail from MTN with the details. They however forward me an sms to rate their service when I actually haven't received any service!!!This somehow seems like a ploy to delay the cancellation of my contract and charge me exorbitant fees which they have been charging me. It is actually this kind of service which has made me cancel the contract with I took out well over 10 years ago. Loyalty is just never considered at MTN !!