They want me to pay again for a service they never rendered

This is how my conversation went with one of their agents.

[11/26, 13:11] Star: Hi Tiffany, I still have an outstanding refund with you guys R399. I paid for installation and I was told that they no longer install in my area because of crime (Khayelitsha)

I am now moving to a new area and I wanted to find out since I have a credit of R399 with you guys can I use those funds for installation in the new area? [11/26, 13:13] Webafrica: *Tiffanys S.*: A new payment will need to be done and then your Webafrica account will be credited still for the other R399 [11/26, 13:14] Star: Okay, thanks. I will try another service provider, as I have been waiting for the refund since July. So I have trust issues with you guys now.