Hey @yoon jun, are you having trouble submitting a help request to our support team?
What you need to do is open a browser that is not logged in to any Dropbox account or even better, use an incognito/private browsing window.
Then, go to this page and in the "I want to look up information related to" section, choose "other".
Then, type in an email address you can access, then select your payment details, describe your issue in the "other details" box and then submit your request.
I hope this helps!