Mango Trench Coat Size Exchange Issue

I bought a men's trench coat from the Mango website. Because the item turned out to be bigger than I thought, I sent it back to the main Mango warehouse to exchange it for the right size. While talking to customer service, they told me that the size I need is in stock at the warehouse, and they will send it to me as requested. But the main warehouse didn't give me any information about my item and just started the return process, saying that there are some issues with the product. The website is still selling the same item. It's clear that I was given wrong information. Also, the cost of the item I bought on Black Friday has gone up. It's obvious that they chose to return the item instead of exchanging it for this reason.