If you are selling your time and exceptional talent for so cheap, you will eventually meet this kind of equally cheap, arrogant clients with their unreasonable expectations. Your time and work worth much more! I would suggest reconsidering your prices ASAP. Furthermore: before start working on a fixed fee project, always make clear to the client, how many rounds of revisions are included in the initial price. (For me, it is two sets.) Every additional work need to be compensated at your hourly rate.