Definitely reset it to wipe all traces of yourself off it.
If it’s black, then put it on eBay or Gumtree; take it to a charity shop that accepts electricals; take it to the local tip and put it in the electricals bin; according to taste.
If it’s white, the last option only.
For either, if you remember where you bought it, they may (have to) take it back, if you just want it properly recycled.
Are you sure you really Cancelled?
It’s easier to get a refund on a Norwegian Blue than to cancel a NowTV Pass.
It takes four steps; miss one and you haven’t really cancelled.
And if you have Cancelled, then you should have an email from NowTV to prove this.
And if you look in My Account/Passes & vouchers, you will be able to see if the Pass is still running or not; if it is, best try Cancelling it again, until the entry there shows it to be so.
But if you have not used the pass since you thought you cancelled it, get in touch with Live Chat and see if you can get a refund:-
Get in Touch (all the options, and the best place to start):-
On a screen with big buttons all around, you may find the link you need is under a tiny green arrow, so be vigilant.
Live Chat and Send Us a Message:-
On Live Chat, when you can get onto it, keep your answers short, sweet and prompt, or it will time out on you.
If the person you are talking to doesn’t seem able to understand your issue, ask to be escalated to the next level of help.
<If you can’t access Live Chat and nothing happens, try a different browser from your usual one (Internet Explorer, Edge, Chrome, Firefox, Safari) on which you haven’t disabled pop ups, third party cookies or indeed any cookies, and haven’t set an Ad Blocker, as any or all of these things may prevent the Live Chat window appearing>
One of the checks that NowTV do is to reserve (not take) 10p on the card that you sign up with.
If they can’t do this from the details provided, then they will decline it, as you have found.
What sort of card is it (Credit, Debit, other (please describe); MasterCard, Visa, other (please describe) with what bank? is it a sterling account, with a UK bank? Are there funds available?
Have you described your name, and any other details requested, exactly as they appear on the card?