Website not allowing us to buy online

Good Morning , <br> <br> I am very disappointed with the service level at Groupon online shopping for three weeks now I have been struggling with a purchase online for a sleeper couch and my fear is its going to be out of stock , When I spoke to the customer service they gave me different options to try of which I did and still there is no solution to my problem , I asked them if they could generate and invoice from their side and send it to me , so I could make a payment as the problem its with their system not mine , I would like this matter to be resolve before the couch will be out of stock.