Worst ISP ever

Been trying to sort out some problems with this useless company , have a statement i have received on the 4th of main showing i have R800+ credit cool , on the 10th i logged in since been having problems with connection being off for 4 days... now on the 19th decided to give them a call regarding this and they tuning me now **** about being billed in advance and my account never showed credit etc and yet i have a email from them stating otherwise..

you guys are useless you keep making excuses to not give my money back only thing you guys do is lie and *****