I sent an email to ask for a refund but I got an email back said that
"A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

This e-mail address is being protected from spambots. You need JavaScript enabled to view it
host ASPMX.L.GOOGLE.COM [74.125.28.27]
SMTP error from remote mail server after end of data:
550-5.7.1 Unauthenticated email from yahoo.com is not accepted due to domain's
550-5.7.1 DMARC policy. Please contact administrator of yahoo.com domain if
550-5.7.1 this was a legitimate mail. Please visit
550-5.7.1 support.google.com/mail/answer/2451690 to learn about DMARC
550 5.7.1 initiative. t68si5223447ioi.0 - gsmtp

------ This is a copy of the message, including all the headers. ------"
Can someone help me please?

Hi Chau,
In order to void email problems, it is recommended to resend your request via this Support Form.
Looking forward to hearing from you.