Terrible service

Terrible service. They didn’t deliver a few items to me due to an inventory error from their side. They said they would refund me within 1 to 3 business working days. It’s a month later, I’m still waiting for the refund. When I’ve contacted them they said they’ve already refunded me, I had to them send them my bank statement to show they haven’t. Still waiting for a refund, it’s ridiculous.