After 25 calls and 15 emails, I am still unable to purchase the 4U Deal voucher, with no progress on the matter

After 25 calls and 15 emails, I am still unable to purchase the 4U Deal voucher, with no progress on the matter. The responses keep shifting—sometimes it's blamed on an error on my end, other times it's said that the First Loyalty Plus development team is working on it. This is completely unacceptable. As a long-time paying member who rarely uses the benefits, my very first purchase shouldn’t be this difficult. The company’s slogan, "How can I make you smile?", feels completely misleading in this situation.