How To Unsubscribe From MTN Backup Service

Have you been having any funny deduction from your Mtn line when you ain't subscribed to Mtn callertunes, mtn learn English weekly and other value added services. Is Mtn deducting your airtime all in the name of backing up your sim contacts? Anyway, am here to put a stop to it. I think many sims are now automatically subscribed to Mtn backup service whereby N50 will be deducted from your line