Topic: Removing old profiles?

I had a few friends over a long time ago to try my wii u. I let them create accounts thinking it would be an easy thing to remove them later. I'm not on speaking terms with either of them and now their profiles are stuck on my console.

Is there any way I can remove them from my wii u without knowing their password?

I heard about the possibility of reformatting but I have a lot of save data on my wii u that I don't want to risk losing. (I read that save data cannot be returned to the wii U once it's been reformatted) Do I have any options?

What to Do:

On the Wii U Menu, select the Mii character in the upper-left corner to access the "User Settings."
Tap "Delete This User."
If prompted, enter the four-digit PIN. If the four-digit PIN has been forgotten, it will need to be reset. How to
The nickname and Nintendo Network ID associated to the account will display. Select "Next" to continue.
Select "Understood" to agree to delete the save data and play times associated with the user. Select "Next" to continue.
Select "Delete."
Select "OK" to return to the Wii U HOME Menu.

That only works if you can actually log into the accounts, which as I said, I cannot.

I don't have access to their Nintendo network passwords, as we are not on speaking terms.

I am wondering if it is possible to de-link them from my Wii U, I am the primary user and I never would have imagined I'd have such a nightmare of a time removing two people from MY Wii U.