How do I verify my number?

I can't even send emails.

Ah, this is so frustrating. I keep trying but it's not working.

I think I used my old number when I signed up, but I don't even remember it. I'm trying to exchange a convenience store coupon, and it's asking me to verify my identity, so I keep trying, but it keeps saying the verification code is incorrect.

How do I do this?

Email sjjin6332@gmail.com

Please check and give me an answer.