Bad customer service

Been a client of MTN for 15 years,2018 took out a contract with them, whereby my prepaid number was converted to contract. Contract ended on June 2020 asked mtn to convert my number back to prepaid. They kept on promising me that they will convert it back to prepaid,now its 3 months without being able to use the number, when contacting them they also take me from pillar to post been assisted by different consultants without any solution.