I was informed by Revolut that the special offer was activated for my account, but I didn't get the promised bonus.
To get your bonus (e.g. cash reward, cashback, free subscription), complete required actions within the specified time limit after activating special offer. Check offer's terms & conditions in the participation invite email to ensure all actions are completed.
Common actions include adding money, ordering a card, making certain card payments (transactions to payment service providers and money transfers won't trigger a reward), and upgrading to a paid plan.