Pathetic service, phone calls not returned. Waiting for a refund for over 6 weeks.

Ordered a computer mouse on the 1st of January. On the 4th they let me know out of stock and will be refunded into my account. Still not in my account. I have phoned five times and sent numerous emails. They keep sending me emails saying that it was refunded on 1 January. The money did not return to my account.