I get notifications that my storage payment source has expired

Scams (e-mail, text messages, and phone calls) are getting very good at closely imitating true Apple communications. Always be cautious. These support articles have some guidelines:

About identifying legitimate emails from the App Store and iTunes Store --> Identify legitimate emails from the App Store or iTunes Store - Apple Support

Recognize and avoid phishing messages, phony support calls, and other scams - Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

Avoid scams when you use Apple Cash --> Avoid scams when you use Apple Cash - Apple Support

Apple 'How to identify, avoid, and report phishing' video--> https://youtu.be/SR3Z3fXXjfw

If you are uncertain about a message and a resource provided in that message, do not click on any links in the message. Try to independently verify the resource by going to a support article page on apple.com and use the instructions in the article to verify though apple itself, or your Apple device features, what the message is claiming. Alternatively, ask Apple: Official Apple Support

Check your iCloud storage usage online or on any device using the direction in this support article --> Check your iCloud storage on iCloud.com - Apple Support

Click on this link to see how to view and mange subscriptions --> If you want to cancel a subscription from Apple - Apple Support

On an iPhone, iPad, or iPod touch

1. Open the Settings app.

2. Tap your name.

3. Tap Subscriptions.