Very bad service

I ordered a control panel for my 3d printer. When it arrived I plugged it in correctly and it wasn't working. I contacted diy electronics immediately. They said they will collect the item, check it out then refund me. I tested it on 4 different machines, and no luck. Now they want to charge me more than double the original price to send it back. I told them to keep their *******. I'm losing the money I paid for it. It's ok, but I did tell them that I'm not leving the case there. Really very very bad service. They won't get my money again