No Response

Ridiculous...I placed an order on Groupon, made the payment and send the proof of payment through to Groupon. they notify me that my goods will be delivered within 14 working days. On the 13th working day, An email was send to me that the supplier was out of stock, I should send my bank details for a refund. I attached the proof of payment that was made to them with my banking details. No one has respond to my email. a month has almost gone by and no one has still contacted me back after a few emails that I had send to them. I tried to phone the number that was on the email, no one answers the phone. they are currently experiencing high call volumes and suddenly the phone's off. i want an explanation!!