EU LDS???
If you're referring to the The Consumer Protection (Distance Selling) Regulations 2000, I've got certain doubts about whether they would apply, since your circumstances might be covered by the exemption under Regulation 6(2)(b):
http://www.legislation.gov.uk/uksi/2000/2334/regulation/6/made
If you have a claim against LivingSocial it's likely to be under the terms of the Trade Descriptions Act 1968 because what you purchased was incorrectly described (i.e. there was no mention of time restrictions).
You could try threatening LivingSocial with legal action. Send a letter to The Company Secretary, LivingSocial Ltd, 25 Wellington Street, London, WC2E 7DA by recorded delivery. (Retain a copy and check online to see that it's been delivered, noting the date, time and signature). The letter should be dated and show both your address and that of the company. It should clearly state that it is a demand for payment, stating the amount and giving the reason why. The letter should also state that if payment is not received within a specified period (I suggest 14 days) you will commence legal action.
Sometimes the threat of legal action is enough to get a positive response. If not, you'll have to decide whether it's worth pursuing the matter further via HM Courts Service's online claims system:
https://www.moneyclaim.gov.uk/web/mcol/welcome
Chris