Hey @Mark G!
Phone/Email verification isn't available for all businesses. It is only available if Google prompts you.
Your verification code is good for 30 days after request, and can take up to two weeks to get to you. After 15 days, you can contact the Google My Business support team via this link- https://support.google.com/business/contact/verification_code_issues
I hope this helps. Let me know if you have any other questions.
If this fixes your problem, please "Mark as Best Answer" to close the forum post.