RE: Problems with the flash card app

I have Chegg's flash card app (3.14.2) on my iPad (iOS 9.3.1). I was enjoying the ease with which I was able to make more than 600 new cards for my students, when I began to have trouble. It seemed to become unmanageable, particularly after downloading a number of kanji flash cards for myself, with the app starting to hang up and crash often. I attempted to use your sync feature to ensure that my work was backed up somewhere, but received a "sync failed" flag. MI attempted to share my flash cards, as well, but the operation did not complete. Currently, I am unable to even open the app. I still have approximately 5 gigabytes of space available on my device and am not experiencing any problems with other apps. Any suggestions--particularly ones that will not require recreating the hundreds of cards that I have already completed--would be greatly, greatly appreciated. Sincerely, mgdavison@hotmail.com