Just today happened the same to me. The client asked me for one code where it should convert one pdf into audio file and then open the pdf and play the audio. I just delivered the program exactly as he wanted but he requested to cancel saying that he didin´t need that anymore.I deny the cancelation because he already had the program and because i sent him what he asked for.
As incredible as it sounds, fiverr approved the order cancellation and even more incredible was the fact that the client got a job for 2 full days for free and the person who worked on it received nothing.
Already talked with fiverr help center and if this case is not resolved in the correct way I don´t want to work with a website that leaves their worker penniless and the client with a job for free.