I know it sucks, but if the ticket was booked on the QR website, it states very clearly that it doesn't have lounge access. So it is really on the third party website for not properly communicating this, rather than on QR.

I don't think it is all that unusual for airlines to sell a cheaper business class ticket that does not include some of the perks. This works out for people that just want the onboard seat and service, or for frequent flyers who will get lounge access anyway.

So, in short, take it up with the third party travel agent, this is their problem, not QR's.