The worst online shopping experience

I bought a heater (24th June 2020)online, and it showed that the store had 5 in stock, I've called the store Robindale builders- and they have been of not assistance whatsoever. I went online and spoke to Craig Roussow, he has also been of no help whatsoever. didn't even respond to my last email. Could someone at least give me proper feedback or my refund back as this is the worst store to buy anything from.