Bad service

I’m very frustrated about the service I received from MTN Simmonds , I dealt with a lady by the name of Sophie Chigbue who was helping me with a additional contract for WiFi - everything was processed and application was approved and she advised that I need to do a a upfront payment , also advised that she need to do something regarding the router , now today they advise that I need to pay more as it’s a new month , I’m not happy !! I need my router