I think the pastime should be some sort of exclusive content (example, videos or 24-hour live streams (and maybe think about including paid advertising during that)) which both the refunded and the non-refunded have access to for the day.
NEP is a dApp (writing it in Rust) but for the moment just trying to build out something that would work as a web app sitting on a server so maybe for the moment links which can only be viewed in one browser at a time.
How to get the links to the refunded and non-refunded? There are no user accounts.
Maybe it can be done by signing a specific message with their private key and the signature can be used to gain access to a link. Not sure yet how this is going to work (it'll get figured out).
The user's private key would need to be for their BCH change address (specifically for the address which was used in their SLP transaction deposit).
NEP dApp does not have a login. No user accounts, no user wallets and does not generate keys for users. Users can use any wallet which both supports SLP tokens and provides access to private keys.