My payment Method continues to get declined no matter how many times I update it and the funds are available in my bank account

..schuyler177..

Perhaps if you've not tried specific alternative referenced payment methods

or paths to choose another different one, those may relate to resolving this.

• If you need to change or update your Apple ID payment method - Apple Support

//support.apple.com/en-us/HT213276

"The first payment card that you add to the Apple Wallet on a device becomes your default

card for that device. ~ When you add more cards, you can change your default card."

• Change or remove the payment cards that you use with Apple Pay - Apple Support

//support.apple.com/en-us/HT205583

And, you may need to add a replacement card to the account, prior to removal of earlier one.

There could be changed instructions among these, please be careful when applying them.

To troubleshoot or attend to issues within the App store, iTunes, and other Apple media carefully check them.

• View your purchase history for the App Store, iTunes Store, and other Apple media services - Apple Support

//support.apple.com/en-us/HT204088

You may need to attempt to renew all those factors, to restore their viability; short of erasure of OS.

•Subscriptions and Billing - Official Apple Support

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

If you made backups, be sure to follow their instructions if attempting to use them; their rules may

differ across device and computer versions. And be careful should you need to restore from backup

from a Computer, and USB cable. Depending on which OS (macOS / PC) instructions also vary.

• Connect iPhone and your computer with a cable - Apple Support

//support.apple.com/guide/iphone/connect-iphone-and-your-computer-with-a-cable-iph42d9b3178/ios

• About the 'Trust This Computer' alert on your iPhone, iPad, or iPod touch - Apple Support

//support.apple.com/en-us/HT202778

[These details matter enough to consider & review them each time, when used.]

Hard to tell from afar what gremlin or pinto may have gotten into your sandbox; haven't a clue/cure.

..As a Volunteer here, my kits cross many vintage and newer Apple products; and decades of use..