From my notes, I've returned 4 ebooks over the last decade+. One was purchased for my wife who found an ebook that used rein/reign/rain and several other homonym sets interchangeably, where the common punctuation marks were endangered species and run-on sentences were a way of life was unreadable after she forced herself to read the first 2 chapters. The other 3 were purchased for me, 1 was returned for egregious formatting errors, 1 was returned for having nothing to do with the supposed topic (a book with astronomy in it's title and then spends the entire book complaining that astrology is no longer a respected science) and the 4th was returned as a purchased in error (the author re-issued a 4 book series with new covers, new titles and an added short story to make these version 2's more palatable. 2 were purchased from Amazon, 2 were purchased from Kobo. Neither gave me any issues with the return though with the astrology book, the CSR did check the book and agreed it was mis-described and mislabelled.
The series book picked up an "
Originally published as" after my complaint (likely due to a number of complaints not just mine but I'm willing to take the credit
).