Charged twice

I ordered a printer from Atomic Parka and paid $260 for it. The printer came fast and I forgot about this purchase until I saw that Atomic Park has charged me twice the same amount. I contacted them a month ago and I am still waiting for the refund. They sent me emails twice already that my credit is being processed. I am not a happy customer. They charged me twice and they are not in a hurry to correct their mistake.