No Alert Or Vibration For Txt Msgs. No Notification Of Missed Calls.

I have a Samsung S380C. The phone I have now is the second one I have gotten in less than a month. Both phones were the same exact model. The issue is that there is no notification of text messages other than the white envelope on the screen. There is no alert or vibration. Also there is no notification of missed calls. I was hoping the first phone was a glitch but apparently not. I have talked to customer service on the phone and also walmart associates about this issue and nothing I have been told to do works. Please help.