Horrible service

I was an an employee of MTN for 12. I resigned in March and requested to be migrated to prepaid. The number was migrated on the 18th of May to prepaid and they have now blocked my incoming calls. I called them and was told that it was escalated to the manager by Samkelisiwe from the call center and of cause kept me on hold when I requested to speak to the manager... I feel bul**** by MTN as I am losing money for not receiving calls