Are you connecting to the test socket with a new filter?
does your phone work ok?
a BT hub4 wont work with fibre , so only a 5 will work.
i have had the built in filter fail on the wall sockets before , so try your plugging the hub in to the master socket (unscrew the front panel and plug the hub directly in to the socket there)
try different filters too
other than that - youll need to call BT
the hh4 does work with fibre but you need to use a separate modem
OP already tried test socket with no imrovement