It looks like there have been so many complaints that the NCA is looking into them.
here's a bit of it:
She said the deal sites can be a great way to items at a good price but stressed “consumers need to be confident that advertised discounts are accurate and that any restrictive terms and conditions associated with an offer are clearly highlighted. For businesses, group selling can be a way to increase sales in difficult times, but as always, businesses need to be mindful of their obligations under consumer law.”
As part of the review, the NCA will examine the accuracy of deals on offer and the extent to which advertised discounts are accurate and transparent. An analysis of the terms and conditions of advertised deals will also take place. The NCA has already begun discussions with online deal site operators.
When consumers buy from an online deal site, there should be no difference in the quality or availability of the product or service offered than buying directly from the provider at full cost, unless it is clearly stated. Your consumer rights do not change because something is offered at a discounted price,” Ms Fitzgerald said