"12. Claims may only be submitted between zero (0) and thirty (30) days after the date of purchase, meaning the final Claim date (for all Promotions) for purchases made on the 30th September 2020 is no later than 23:59 (GMT) on the 29th October 2020 (“Claim Period”). Claims outside of the Claim Period will not be eligible for a Reward. For the avoidance of doubt, the date of purchase counts as day one (1)."
I copied this from the Ts&C's of what I believe is the promotion you went for.