Same problem here wanted to buy the special offer but everytime the card is declined, WTF. please fix and expand the time. Support ticket doesn't help. Browser changed and cache and cookies deleted and i don't have saved the card.
Update 26.08. 13:46
anweser from the support team:
Thanks for nothing the special offer will end today and it is not possible to buy it because of the change of the bank.... so the creater of the game doesn't want to have the money, sorry but I do not have any understanding for this.