My virgin hub keeps resetting back to default user name and password, it's done it 3 times in the last week
Do a pinhole reset to factory settings. Push the pin in to its stop point and hold for a "timed" 40 seconds do NOT restart the router after that. See if that sorts it - if not report back.
-------------------- Services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.
The pinhole reset held for a couple of weeks but I've just restarted the router as it had dropped all connections and was not allowing ethernet or WiFi connections - its now accepting connections again but the settings have again reverted to default