Takes years to migrate cellphone number to prepaid

Service i get frm MTN is shocking my contract ended on the 26th of April and i called customer care to to migrate my number to prepaid as i do not wish to upgrade, i was advised my request will be processed in 2 days i got a *** then i wated for an sms that will confirm that this is now done. On the 28th got an email frm retention asking real reason why i want to migrate to prepaid i rep**** to the email then got a no rply email still saying query will be resolved in 2 days 5 days after i called customer care and they said case will excallated and this will be done in 2 days but still am still on contract called again today as yesterday's 2 hrs has passed and customer service promosing another 2 days wich i dont wanna wait for i really need to knw how many years will it take for this to be done.....