How can reset my WiFi password as it seems to crash it say wrong username and password to reset and delete all devices on it
Perform a factory reset to the router.
I had one of the customer service lwrsin do that and it dosent seem it has reset it and when I tried to reset it again saying wrong username and password
You need to do a factory reset, which means holding the reset button in for at least 10 seconds,
The username and password will then revert to those on the router.
See this video for the Sky Q router, which is the same hardware as the Now router.
(32) How to factory reset a Sky ER115 Router Sky Q Hub - YouTube