Include phone verification and payement verification.
Fiverr have already huge competition, but then there are other sellers who rate themself 5$, making multiple accounts and making loads of money because of cheating.
Fiverr cant detect those kind of cheaters, but fiverr should do something about it.
PHONE VERIFICATION - yeah, still they can cheat this but it would be more difficult.
PAYMENT VERIFICATION - that could totally solve this problem. They can earn, have money on their balance but before deopsiting money they should provide ID verification.
This could help sellers a lot! Please think about it!