Hi, I am not able to update my billing information. Each time I try, I get an error stating that "Your payment method was declined. Update it or add a new payment and try again." I am not able to update any apps due to this. Please help. Thank you.

See the Apple Support article(s) below. Link to contact Apple Support in the article. 

Apple ID payment information - If your payment method is declined, or you have a billing issue with a previous purchase in the iTunes Store*

Possible fixes.   Fix ‘Your Payment Method Was Declined’ Error In App Store.  -

                          Payment method declined in iTunes or the App Store.   -

What happens when you try? Error message(s)? More information would help.

Log into your account in the App Store/iTunes and you should be able to change/verify it there. Or you can click the blue Edit payment methods in the article below. When signed in and the page loads, you will be on the credit card page. After updating that, click the Go Back button at the lower left and you will be on the address page. If you have a subscription, you need to add the new card, and then promote it to the primary payment method before you can remove the old card.

Apple ID payment information - change.  *

You are welcome.

hi

won't let me update billing card information with new card