I am having the exact same issue, upgraded hub 2 to 3 from 200mb to 500mb. Impossible to get through to technical. Reset Router 3 times still the same. Internet access denied when connecting to dashboard. Phone 0800 number and hub is activated and online.
I've swapped back to my hub 2 and its working fine.
Thanks for using the forums to get this issue looked into, I am sorry your new equipment did not work upon installing! I understand how frustrating this must have been for you. However, I have checked our fault checker for your services and can see the faults team fixed this issue for you. Can you give me a quick update on how things are on your side please?
If you're still having problems, please let me know what is occurring 🙂