@Anonymous User
Welcome to the forum. Have a look at the following help page which might be of use
https://help.nowtv.com/article/merlin-entertainments-free-pass-offer
If copying down the code and going to your My Account > My Passes page and clicking the apply a voucher link next to your choice of pass to apply the code manually doesn't help then try having a word with live chat.
You can get to live chat from the Contact Us page
https://help.nowtv.com/get-in-touch
(choose the options that apply to you, or expand the Anything Else section)
