It sounds like you've migrated from the TiVo to a TV360 - https://www.virginmedia.com/care/tv-fault/which-tv-box
If so, then migrations to TV360 are voluntary but also irreversible. It's quite common for VM sales to offer a conversion as part of the re-contract process, but it's never compulsory unless part of the package was Disney+ or Paramount+ which are not available on TiVo/V6.
Once your account has been migrated to the TV360 platform, then any reversion involves a complete rebuild of your account - which VM will not undertake lightly. The TiVo's are also being actively replaced with V6, which run the same software.