No response and wrong order delivered

I ordered a gold drinks trolley and a black one arrived. I sent it back and then was told I couldn’t exchange because I had ordered a black one. I sent screenshots of my order for the gold one and was told that there was a glitch in the system and now there is no stock of the gold one. So I looked on the website and there was still stock and I could add it to my trolley. No one will get back to me and I’ve phoned about 6 times. All I get told is that it’s escalated and someone will get back to me. But I keep getting emails saying my black drinks trolley is on its way? This is pathetic.