Still no refund received since December

I had purchased 2 products from Groupon and 1 got delivered and the other product did not even arrive. I called Groupon on several occassions asking about the status of the product. Groupon call centre agents promise to call you back and send you emails but they never do. I purchased these products on the 27 November 2015 and cancelled them mid December and still have received no refund. <br> <br>