Shocking service, broken promises, and withholding my refund!

I bought a Kenwood kMix glass bowl from The Culinarium a month and a half ago. They sent the incorrect model. I notified them immediately, but they repeatedly failed to communicate, forcing me to follow up over several weeks. Eventually, they admitted they couldn't supply the correct part and agreed to a return and full refund.Their courier collected the item over a week ago, and communication entirely stopped again. When I phoned, they claimed the courier lost the parcel. That is a dispute between them and their logistics provider—not me. I have followed up multiple times since Friday, Monday, and Tuesday. Every time, I am promised the refund will be processed "before the end of the day," yet deadlines pass and I receive nothing.The Culinarium now has their item back, they have my money, and I have nothing but broken promises. Avoid buying from this company if you expect basic consumer accountability or reliable customer service.