How do I get rid of needing to verify a new number?

Change your country setting back to where you actually reside. The support article Change your Apple ID country or region - Apple Support describes how to change your country setting on everything using your Apple ID, and the requirements and results of doing this.

Changing store country is not a trivial endeavor. The system is designed to only facilitate doing this if you are moving to the other country to take up residency. It makes it difficult for people to temporarily change country settings to do things such as get around distribution restrictions only allowing them to buy items available in the country where they live.

Contact Apple. I remember there being various differences in how things are done with China but I don't remember exactly what they are.

Refer to this page for Apple Support features ➔ Contact - Official Apple Support

Select from the presented options until you find a solution for your issue, or see if there is a chat or phone call contact method offered lower on the page (you sometimes have to narrow down the options multiple times before this is shown). If you do not see your issue, keep experimenting with any series of selections until you reach one that offers a chat session or a telephone call and get the representative to redirect you.

This support article has various country telephone numbers for contacting Apple for support and service ➔ Contact Apple for support and service - Apple Support