Refund me my money.

I bought a coffee table from their market place ‘online’ store. They charged me twice on my account. Table was delivered and they emailed me that they are processing the refund. I have been waiting for 6 days and there is still nothing. I called the contact centre and the agents drop the phone after hearing my query. There is no direct line with refund department. Now I have to suffer bank charges as the money was there for debit orders that have now bounced back. I just need my money.