Welcome to the forum. There's a help page on the Snatch promotion here which might give you additional info, and if you need to contact NOW TV click on the green Contact Us button at the bottom of that page and you will get options for live chat or send a message (no phone number I'm afraid)
Firstly i would read the attached help linked article to make sure that your current snatch prize complies (for example you can only win one nowtv prize for each type of pass every 6 months etc).
If you believe that you fully adhere to linked article and for some reason cannot claim your two month cinema pass , then i would suggest contacting live chat by opening the linked page below, scroll towards the bottom of the article page and click on the green contact us button, where a secondary page will open giving you the option to contact nowtv by live chat or email.
@monty2883 If the cinema passes came with a NOW TV box then they can be used by existing users. If you currently have a cinema offer on your account you'll need to wait until you are in the last month of the offer before you apply another one. If you get a code inot valid message the following help page might be of use.
Was as there any wording on the box that suggests the codes are for new customers only.