I need to know what happens if a seller is the one to initiate the cancellation request and what happens if a buyer initiates the cancellation request? Do both affect the seller’s order completion rate, gig stats and selling in same way? Or one is less bad than another?
And if we are in situation of cancellation, should we cancel it ourselves or contact CS? Can CS prevent the impact or order cancellation on completion rate?
In case seller is not responsible, and this cancellation is unfair.
I also need the answer to this question. A buyer is currently harassing me and plaguing my notifications with cancellations requests AFTER I’ve completed the work. At this point I want to initiate cancellation but don’t know what that entails.
(I’ve reported said buyer to CS though)
Any help provided to this post would be much appreciated 
Both effects same. Both will hurt your performance.
At first if you are all OK. Then Struggle with buyer until cs responds. Then they will advice what to do. Don’t forget to gather as many as proofs.