Error 7400 is a TiVo-software activation error, so it sounds very much like there's a mismatch between the software your box is running, with what it's trying to run, and what VM's provisioning systems want it to run. The first 2 say TiVo, the final one says 360.
If CS can't fix that remotely, a tech visit is the way to go.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks