How can I verify my Email address for the im30 account if I don't receive an email?

You will need to receive the email to verify your address. Check that you have entered the right address, and also check if your email account has a junk box or spam filter that might put suspected emails in a different location. Automated emails will often be filtered out.

If you still cant get it then try contacting the developers for more help.

https://www.appgamer.com/last-shelter-survival/strategy-guide/how-to-get-help-in-the-game