The Courier guy I want my refund

I've cancelled my order with them and requested the refund, they asked for the letter with my signature, copy of my I'd and my bank statement which I sent a month ago . They promised to refund me within 7 to 10 days ,it has been month now, I've been waiting for the refund. They are no longer responding to my emails. I've sent numerous emails to the company but I haven't received my money. I'm so disappointed on them.