Thank you for getting in touch with your issue, I'm really sorry that you've had difficulty using certain TV services.
If this were a problem with the physical remote only, I'd suggest that it may be a faulty remote. However, you've advised that the app is also affected, so this makes me wonder if it could be the box itself.
First of all, I'd like you to try manually connecting to the network by following these steps: press Home on your remote > select Help & Settings > select Settings > select Network > select Connect to the Virgin Media Service now. Let me know whether this helps and we can take it from there.
Our TV team have suggested that you may have accidentally selected a higher Video Output to a higher resolution than is supported by your TV. You would normally change this via the settings menu, which I appreciate you can't access right now (Evidently I was having a moment when I asked you to reconnect yesterday!) In this case, do you have another TV which you could connect to the box to gain access to the menus?