Is won’t let me use my iTunes balance start music again and it won’t let me remove a existing debit card that is no good

Greetings, Elinor-43!

Thanks for reaching out to the Apple Support Communities! It sounds like you're having an issue using your iTunes balance to pay for your monthly music subscription. In order to have a subscription, you will need to have a valid payment method on your Apple ID along with the iTunes card to ensure a payment method is available if the gift card balance is depleted. Check out this article to Join Apple Music on your iPhone, iPad, iPod touch, Mac, or PC for more information.

Since you're having an issue changing the debit card for your Apple ID, we also suggest checking out this article If your payment method is declined in the App Store or iTunes Store for steps you can take for issues changing the card information on your Apple ID.

"If you still need help, contact Apple Support."

Cheers!