Help! Secondary email disappeared

Me again sorry!

My secondary @ntlworld email account has disappeared, it's not even showing up on the primary account?

Up until I reinstalled email client I could send/receive (just no access to webmail)?

I've tried accessing from webmail but just stuck in an endless loop of reset password/forgot email/not account holder options.  (If I go into primary @ntlworld account it's not even showing up)

I had to generate an app password sometime last year but forgot to save it and after reinstall on email client I now get "unable to verify email/password" etc. 

The help page options haven't helped. It's so frustrating, I've had the account for over 20 years...any help will be gratefully received!