My friend bought a phone, and got the $10 unlimited messaging card and it worked all day and was texting with it all day then the next day it didn't work. We then traded phones and i bought a $10 unlimited messaging card thinkin he put it on wrong, and then it did the same thing the next day and it said, insufficient funds to send message, so i thought it lasted 30 days but apparently not, How do these phones work?