Groupon and shark cage diving ****

On Monday 27April 2015 I bought a groupon Voucher to the value of R1100. On Wednesday I called the following number *** to make a booking. Ever since then when I call to confirm, it's a different excuse to confirm my booking and they can't accommodate me. Today, Saturday, 02 May 2015, I called another number on the groupon *** and spoke to Sheryl - she explained that the company listed on groupon is no longer in existence and she made another booking for me to shark cage dive at an additional cost of R1600 and told me that my groupon voucher is no longer viable and I should discard it...why should I pay an amount more than I originally paid if all these numbers are listed in the groupon voucher? I'm leaving back to Johannesbug on Monday and the desired outcome is either a full refund or that the company pay for me to come back and shark cage dive.