Square held my deposit

[Db1279]

I sold gift certificates to a clients father. He buys around $750 I gift cards every year for my client and his wife. He called me yesterday to do it again. I sent him the link to my square gift certificates and he bought $760. on a cc. I received a message from square saying they detected fraudulent activity. Most of my sales through the year are under $500. But this one client every year. I called customer service to verify the transaction.They we're not only unhelpful but extremely rude about it. They sent me a form to fill out( which I did. ) They are say they need more info such as a invoice. I don't have a invoice because this was done through my square app. I sent them a copy of the transaction but I don't have anything else. My client can't print out his gift certificates ( which he wanted to give them last night)

Anyone know how to deal with this problem?