No service at Cotton On

Cotton On's service is very poor. They tell me I have a store card so I can receive and use discount vouchers but Cavendish Square doesn't have any cards at all in stock! So what's the point of even filling in the info they asked me to give them? So they say when you get your vouchers you will get a card and all you need do is give them your email address in store and you'll get a card and can use your voucher/s. But when I try to get a card and make use of a discount voucher at V&A Waterfront store, although the manager herself said all that was needed at the till is my email address, suddenly they change their story and no I have to have the actual email on me in order to get anything. Both stores are unhelpful and the manager at V&A Waterfront simply changed her tune after I asked for her when at the till. The staff are not informed, unhelpful and frankly service is non-existent. They can keep their card/vouchers/products, I'll shop elsewhere in future.