I can’t update anything

What about billing information? More information would help.

Declined?

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.   -

Apple ID - Payment methods that you can use with your Apple ID.   *

Apple ID - mobile phone billing as your Apple ID payment method.  *