Unauthorised account changes

My contract account was migrated to a prepaid account with no authorisation by myself. There was no communication from MTN regarding this. <br> I am simply told, when querying who authorised the cancellation/migration, that retentions will get back to me. <br> One cannot simply cancel a contract - surely there should be security questions involved and communication to the customer?! I find the service absolutely disgusting and trying to get someone to assist is near impossible. <br> It is not for me to go to an MTN store and apply for a new contract when I never cancelled the first one! <br> It is further impossible to get hold of a manager at head office - the lines just ring and ring. <br> In addition to this, when logging in on the MTN active site, I see an account for another individual with my billing details and cell number. How on earth is it possible for customers to be treated like this.