What if Hugh sends a text message from the website to the user's mobile phone, and then the user replies to the text message through the mobile phone to verify the function of the user's mobile phone?

You write code in the background of the website.

Read the email first, and then:

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If the content of the short message is equal to "Yes" or "A" or "1"

Then the user agreed.

Then do the following.

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If the content of the short message is equal to "No" or "B" or "2"

Then the user disagrees.

Then do the following.

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If the content of the short message is not equal to "Yes", "No" or "Space bar, input key, special symbol, etc."

Then reply to the user, "Your code is wrong, please resend it. If you don't reply within 10 minutes, the system will default to No.