My Client Has Problem With GoDaddy Auctions!

Hello,
One of my client used Godaddy to sell one of his domain, the buyer says that he paid Godaddy but the domain is canceled from seller account and no news about this sale! My client contacted godaddy support via email but they don't understand the issue, He asked me to help him, can any one know one of Godaddy staff here, perhaps he can help us?
Thank you in advance