Is the box connected via Wi-Fi or Ethernet?
You tried to unplug your router and box for a few minutes?
Is the box fully updated?
Worst case you set it back to factory settings.
There are endless threads which contain the method on getting in touch with staff. However they will get you to do the standard troubleshooting which I’ve described.
There are no customer service advisers on this C2C Community 😢
But since you say ‘or other apps’, I presume this is a complaint about Now Broadband?
If so, here is a link that will enable Now Broadband subscribers to access a telephone number where they can indeed speak to Now Broadband support:-
and will enable people who only have Now streaming to contact Live Chat, where they can discuss their issue.
However, if you are not with Now Broadband, you may do better to contact your ISP in the first instance.