You can read the below article for more information regarding this. https://www.fiverr.com/support/articles/360010978618
Seller Protection - Fraud Chargebacks
Fiverr Has Your Back!
In cases where the service was provided in full, Fiverr will protect you from fraud chargebacks. The funds will be added back to your account, and after 45 days, you will be able to withdraw the funds. Most importantly, it will not affect your cancellation rate.