The reason you're not able to send to non-iPhone users is that they don't use iMessage. It sounds like your regular (or SMS) text messaging isn't working, and all your messages are going out as iMessages to other iPhones. When you try to send a message to another phone that doesn't use iMessage, it won't go through. If you go to Settings > Messages, see if "Send and SMS" is turned on. If so, then something is stopping your SMS. That's not a setting on the phone - it would be an issue with your carrier, Verizon. Each phone has its own line of service, so it's very possible for your SMS to be blocked or not working on your phone, and working on every other phone on your account.