Can't make supplier stick to deal bought

I am actually quite disgusted with the way Daddy's Deals(vaguely)dealt with a complaint I made. I bought a voucher for a Zip Line ride for 2 people, this voucher came with a R50discount voucher per person for quad bike riding - there were NO limitations/conditions mentions. I emailed the supplier to get their price list &availability. On this pricelist they listed a 1/2 hour quad bike tour - not once did they say that this was \not a usual tour\" or that it could not be booked except for team building (if this is the case, why is it on their normal price list - or shouldn't it at least say by arrangement only, or for team building only - or something similar?).When I tried to book for the zipline & 1/2 hour quad bike tour through the voucher, I was suddenly told by the supplier that the voucher was not valid for 1/2 hour tours, only 1 hour tours (this was NOT listed as a condition!) when I pointed that out, suddenly the story changed &1/2 hour tours were only available for team building? Daddy's deals have done NOTHING to fix this, they offered a refund - surely they should make the supplier stick to the deal purchased? If not, why on earth buy from them?Have now been ignored. "