Groupon & their merchants don't want my business

On March 23rd, I purchased a voucher online from Groupon to the value of R900. I contacted the merchant that same day to schedule an appointment, but was told by the employee during the second call that the date I wanted was fully booked. The first person I spoke to attempted to accommodate me, but the second employee seemed in no mood to go the extra mile. I let it go, and then some time passed. I called again on 6 May for an appointment in June, and was again told that all the weekends were fully booked. Even after telling the employee that the voucher expires in June, she insisted that they were fully booked. At no point did she even suggest an alternative. I found this already to be infuriating. Then I contacted Groupon via email also on 6 May and requested a refund. As yet, the only response I got was an automated one. I am told that I needed to request a refund within 7 days, but Groupon cannot even respond to my queries within 7 days. I refuse to accept Groupon credits in lieu of my money, because I can find many establishments who can treat me with the respect and professionalism that my patronage deserves. I will not shop at Groupon again.