Iphone MP3 player keeps resetting to zero
Hello. I have the 4S, running ios7. I have had this issue in the past. I use the music player that is installed on the phone and listen to audio files that are 4 hours long. What happens, way too many times, is I will pause the audio, close the player, later in the day come back, open the audio player and the mp3 I was listening to is reset to zero. I then have to try and remember where I was at and then scrub around and find where I left off.
I have been taking screen shots of the music player so that I will remember where I left off. This is frustrating and cannot understand why it seems to reset itself at random times.