Africa Mobile please I want my money back I don't owe them

I took out a cellphone contract with them in March 2022 then was asked to pay upfront money which was to secure the deal between me and them then started paying 499 monthly for 24months which ended last month 30 April 2025,now they were supposed to reverse the upfront money that I paid but they don't want to they want me to sign another contract so that I don't forfeit my upfront I don't want anything to do with them their service is bad I just want my upfront money back that's all ad I'm done paying them