Shocking service!

I purchased an inverter and solar panels on Saturday 13/05/23. They inform me only on the Wednesday 17/05/23 that the inverter i've bought is no longer in stock. They offer to sell me another inverter that wasn't even yet listed on their site at a higher price (which would only arrive in 2/3 weeks time. So i asked for a full refund. I am still waiting to receive my money back 18 days later. I have phoned them multiple times and they are saying that the money has been processed but they stall on sending me a POP. So i am now sitting with no product and less money. You be the judge on this situation.