Nintendo Netowrk IDs

[Eidolon]

Can someone explain this to me please, I'm a bit lost.

https://www.nintendo.co.uk/Support/N...D-1770629.html

this bit - The ability to use a Nintendo Network ID to sign in to an existing Nintendo Account or to create a new Nintendo Account has been discontinued. We apologise for any inconvenience this may cause.

I'm using a WiiU and 3DS. I've forgotten my password, and can't find the email address associated with my account as of yet.
I'm trying to log in properly and see if I can add some funds for a couple of 3DS games in the sale. Does this mean that my existing account is invalid, and I can't get into it anymore?