Why I keep getting billing issues?

Review this Apple document which may give you a lead for your personal circumstances. We here have no connection with the accounts department.

https://support.apple.com/en-us/HT203005

If necessary, contact iTunes Support. Scroll to the bottom of the page in the 2nd link.

iTunes Support

iTunes Support – world wide

Look at the purchase histories of all accounts linked to the card : See your purchase history in the App Store or iTunes Store - Apple Support

Hi

I just have been charged for $ 19.99 but can not figure out what for. Cam you please help me with this issue?

If it isn't in your purchase history, contact iTunes Support for assistance.