what's going on with my billing?

First, your are not asking Apple here but other end users. We cannot look up Apple records.

If other users' recommendations is not what you want, there is a link at the bottom left of this page to Apple Support.

Did you recently make a purchase? If so, issues with billing show up immediately, not latter. Most notes recevied in the absence of any purchase of payment are scams.

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