Youtube Premium

How exactly are you paying for Youtube premium?

Through your Apple ID? Or directly with Youtube on your YouTube account?

Make sure you are logged in to the Youtube app, with the account that holds the Premium subscription.

Try reinstalling the app, it worked for my mom

...but on my Iphone I dont have youtube premium...

If you never signed up for that service, this article applies:

If you see 'apple.com/bill' on your billing statement - Apple Support

The most important part of that article is "View your purchase history." If Apple does NOT show a record of the charges in your history, it is very possible that scammers have gained access to your credit card or bank number and are pretending to be Apple. It happened to us.

If that is the case, only your CARD ISSUER or BANK can remedy it.

If Apple’s purchase history shows the purchase, continue with the instructions in that article.