I am being charged 9.99 monthly on my credit card and my account doesn’t have any subscription

If this is a subscription set up by another person, you can not. When setting up Family Sharing you agreed to pay for anything they did that was not covered by money they had from gift cards.

https://www.apple.com/legal/internet-services/itunes/us/terms.html

"The Organizer's payment method is used to pay for any Transaction initiated by a Family member (except when the Family member’s account has store credit, which is always used first). "

You can remove a person from the group or cancel the group entirely if it is not working the way you like:

Leave [/Cancel] Family Sharing - http://support.apple.com/HT201081 - How to leave a family sharing group. How to cancel it or remove anyone over 13 if you are the organizer.

If you still have problems,

iTunes [Store] Support - Use this form for assistance with account and billing, code redemption, or purchase questions -->

https://www.apple.com/emea/support/itunes/contact.html

or:

Contact Apple for support and service - "See a list of Apple phone numbers around the world." - https://support.apple.com/HT201232

I assume you have carefully read the article I linked in the first post? This is indeed a family sharing subscription issue?

If it is indeed a family member who made the purchase and you are the organizer for that group then you are responsible for paying for their purchase if they do not have enough money in their account balance to pay for it. If you do not agree to do this then close the family sharing group or remove that person from the group. By being the organizer you have promised to Apple to pay for purchases if the person does not have enough money.

You can contact Apple using the support feature at the top right of this screen. Apple does not normally use telephone support as the first line of contact with purchase problems, probably because most problems can be resolved with self-help online a lot faster that you waiting for somebody to respond to your call and call you back.

Click on the link to read what to do "If you see ‘itunes.com/bill‘ or an unfamiliar charge on your bank, credit card, or debit statement" --> https://support.apple.com/HT201382 - Does not mention purchases made under Family Sharing which might be charged to the organizer's card but will not appear under the organizer's purchase history or subscriptions. Ask family members about those or check your receipts.