Hi @shile zi ,
I'm glad that you were able to resolve your issue and thank you for posting your solution so that others experiencing the same thing can easily reference this! Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others ", I'll repost your solution in case you'd like to "Accept " the answer.
Issue:
You submitted an Identity validation for a public certificate and after four days did not receive a request for more documentation, and the validation state said "in progress."
Solution/Root cause:
We checked internally and the request submitted went through.
The root issue was that when filling out the validation form, the company name cannot have an LLC or .com and the address just has to be a street name, with no c/o or additions.
If you have any other questions or are still running into more issues, please let me know. Thank you again for your time and patience throughout this issue.
Please remember to "Accept Answer" if any answer/reply helped, so that others in the community facing similar issues can easily find the solution.