make sure that you have a notification set up for it. if you dont have a notification set up, it doesnt go off. also make sure that the sounds isnt all the way to vibrate. i know mine didnt always go off when it was on vibrate. also make sure the desired time is right and the desired repeat is set too
I'm having the same problem. Your issue was more than a year ago, so you probably have a completely different phone by now unless your "fix" with taking out the battery & putting it back in worked permanently for you. I've had this phone for more than a year, & this issue just started 2-3 weeks ago. None of my ringtones will play, & none of my alerts or alarms will sound. I took out the battery & put it back in, and I even did a complete restore on the phone & nothing has worked.