Need help. How to report seller?

[sisiliamo]

I have a vendor that he asked more money after I ordered and it is for 5 time of the gig price. 

The request I have is lesser in scope. His gig has writing the full policy with the research for best practices. I already wrote the policy myself and just wanted him to check my work and fix the table of contents. I even provided links with example instead of needing him to do his own research. 

I also offered more time instead of the 1 day delivery he listed, I am giving him 2 days. 

I told him to cancel the order as I do not believe in such dishonest business practices. 

After I cancel the order, there is no place for me to leave review and report to Fiverr. Where can I do that? 

PS: I have deal with many Fiverr sellers, some awesome one and some okay one, but never has such a negative experience. I tip very very well (20-100%) and leave good comments for the vendor that really do a good job, and choose not to rate the vendor that I know tried but the product was only average. I have never left a negative review before but I think I will break it for this seller. Please let me know how to report so other buyer is aware before placing the order.