Empty promises of expired promos and discounts

I received an email from Lift this morning reminding me to check in for my flight tomorrow. The email also started that I could get up to 40% discount on my Uber trips to and from the airport with promo codes and links to Uber. When I tried to check in I saw my daughter and I would not be able to sit together, I contacted Lift via WhatsApp and email (they don't have a call centre) and although they where slow they managed to sort out the seating, for which I am grateful. When I tried to follow the link for the Uber promo it turns out the promo link has expired even though it was sent to me this morning. When bringing this under the attention of Lift customer care they said the promotion with Uber ended end of September. So, now, although I was sent the promo details and codes this morning 3 October with promises of up to 40% discount they are unwilling to honour the promo deal they sent me this morning.