Groupon is USELESS!

I tried to make a booking to go Zip lining, for some reason my order would not pass the processing phase even though I've already made payment. To sort this out, I sent 2 emails to Groupon without them getting back to me, I then tried to phone them, only to get a number that is apparently experiencing technical difficulties, an operator asks me to phone back in 30 minutes, when I do the same problem occurs. I would like to receive a full refund as I wanted to do the Zip lining on a specific date. I'm disgusted with the lack of service from Groupon.