This is my second time when this happens to me, I dont find it fair that I wasted 15hours on someone delviery and make constant changes only to be cancel,I really believe that the seller should recieve at least a part of the money for the hours that we spent…just saying
You could create a suggestion for a change in how it will work in the suggestion section. Maybe it could have a poll so we could see how many wanted the change in the way it worked, eg. to allow partial refunds or something like that. Or maybe you could contact CS through the helpdesk re: that order and say everything ordered was delivered or just about the new feature. You could also decline the request from the buyer but they might keep asking to cancel and eventually leave a bad review if they couldn’t get a refund.
Hopefully Fiverr will at some time see suggestions for improvements to the site like they did previously (eg. maybe a mod or someone could send a link so they get to see them).