H1b denial due to not responding verfication mail in spam by client

My h1b got denied due to my client didnt respond to a verification mail sent by USCIS. Its not my client mistake because the mail went in to spam (junk) which they didnt notice it.
After my denial my employer contacted client and they came to know its in junk so they immediately replied to the USCIS mail.

Now my concern is how to proceed regarding this case?
Will USCIS can change there decision if I take an appointment and talk to them. Please help me. Thanks!

File a MTR or an appeal and submit this as the explanation. You have a valid case for USCIS to review the case and overturn the decision (if the denial was solely because of lack of client’s response).