Change your password and don't let her use your account. You can ask for a refund but Apple does not have to issue refunds and may say no if this is happening because you are not taking steps to prevent it.
Here's how to request an app or media refund from Apple (From: Request a refund for apps or content that you bought from Apple - Apple Support - see the article for more detail.) If you bought this in the EU from a third party, see: About purchases not billed through the App Store or the App Store’s In-App Purchase system - Apple Support instead.
1. Sign in to https://reportaproblem.apple.com
2. Tap or click "I'd like to," then choose "Request a refund."
3. Choose the reason why you want a refund, then choose Next.
4. Choose the app, subscription, or other item, then choose Submit.
If you were charged for a subscription that you no longer want, you can also cancel the subscription using the directions in this article --> If you want to cancel a subscription from Apple - Apple Support
Read this support article for information about how long it takes to receive a refund (if you are granted one), and how to check the status of a refund for apps or content that you bought from Apple --> Check the status of a refund for apps or content that you bought from Apple - Apple Support
Apple’s position appears to be that people need to be proactive with purchases, canceling subscriptions at least 24 hours before trials end, and ensuring that others are not able to make purchases on a user’s account. Note that if you allow another person access to purchasing on a device, or through Family Sharing if you are the Organizer, you are taking responsibility for things they do. Apple offers these proactive features:
On your device you can use Screen Time to prevent unintentional or unauthorized purchases from the App Store, in-app, and other Apple services. —> Use Screen Time to turn off in-app purchases on your iPhone or iPad - Apple Support
Also on your device, require a password for App Store and iTunes purchases —> Require a password for purchases in the App Store and other Apple services - Apple Support
Use Screen Time as part of parental controls on your child's iPhone, iPad, and iPod touch —> Use parental controls on your child's iPhone and iPad - Apple Support
If a child made this purchase on their device and you are the organizer in a Family Sharing group, consider activating Ask To Buy—> Approve what kids buy with Ask to Buy - Apple Support