Misleading information and sms

I went to Game at the Glen with parents who are (77 and 82) pensioners. My mom has received numerous sms's that state that pensioners get 10% discount everyday at Game. Nowhere in the sms does it state that you need a game pensioners card. When we got to the till to pay they would not give her the discount because she didn't have the card. We called the manager and he was not helpful at all. Same attitude as the teller. No card no discount. We explained that the sms was false advertising and that it was not fair and that nowhere did it state that they needed a game pensioner card. He said that there was nothing he could do and if she wanted discounts from now on she should apply for a card. He was rude and unhelpful.. They are pensioners who dont drive anymore so I need to take them around, its not as if they can go to the shops whenever they feel like it. I am so angry at the attitude of the staff and manager towards elderly people.