I am new to fiverr and not sure how buyer is protected if any gig is not delivered as agreed or expected ?
Fiverr works like an escrow, meaning the seller would only get paid 2 weeks after your order is complete (1 week for sellers of higher level), untill then Fiverr holds your money for a clearing period.
There are also a few things you can do before an order you’re not happy about is marked as complete. You can refuse to accept the delivery and request revisions (if they are included in the gig you purchased) or turn to resolution center and open a dispute if there are any issues. Order only marks as completed either when you accept it or if you don’t do anything about it for 72 hours.
Suggest you read the Terms of Service at the bottom of the Fiverr main page for the rules as to how Fiverr works before buying.
Everything is explained there in great detail.