Ridge Powerbuild Witbank

I did an exchange of 9kg gas bottles with them they gave me 9kg gas bottles one named EPG and the other is petro gas but today 25/08/2021 I went there to do my exchange as normally it's where I do my exchange they refused to take the gas bottles for exchange which I have received from them with previous purchase with them. I'm not happy with Ridge Powerbuilder at Witbank