Audiobooks on JAM

I have been using a jam for about a month. I use it exclusively for Audiobooks which I download from my local library. It had been working great up until the last couple of days. Now it cannot hold the place after I pause or if I use the sleep function. I reset it a few times but to no avail. Im not sure what changed. If anyone has a clue as to how I can fix this problem, please let me know. Thanks