I have passed through the very same situation recently. I contacted the CS about the issues and they answered me like this
"Thank you for contacting us regarding this. I do apologize for the inconvenience this may be causing you. I reviewed the order, and I see that there was a chargeback filed for the payment of this order outside of Fiverr. The funds are now being held by the payment vendor, and are not in our hands.
Please note that whenever a transaction is being reviewed by a payment vendor, we may be required to cancel a transaction or put it on hold (for example - stolen credit card or other fraud activities). This is part of the service we provide to maintain a safe environment for our users.
Keep in mind that when you don’t get paid, neither does Fiverr, and that we want every Gig order to be successful. If a buyer abused his payment privileges, it is something literally beyond our control, but our Trust & Safety Team is already reviewing this buyer’s actions.
Buyers who do file disputes on their payments made to Fiverr, whether intentional or purposely held by payment vendor for security screening, must resolve those disputes in order to participate again in the Fiverr community, as they are in clear violation of our Terms of Service."