Ok, then the issue isn't with any data stuck in your messaging system.
There is only one thing left we can try, and if it doesn't work then the issue lies on Verizon's servers, and not on your phone.
We can try a complete reset of the device. You can backup text messages if you need to, with the app you just installed. As long as you have a Google account synced to your device, your contacts, calendar, etc. will be re-synced to the device after you run the initial setup again as long as you sign in with the same Google/Gmail account. I do recommend you go to gmail.com on your computer and click on the contacts link, then check all your contact groups to make sure the contacts are synced(if not, ask me about contact backup instructions). Any apps you have, you can also get back by opening the Market, pressing Menu on the phone and choosing "My Apps".
As far as any data that is stored on the SD Card(images, music, etc.), it will not be erased. Only the phones internal memory is formatted.
To complete a Factory Reset follow these directions:
- Remove the battery.
- Replace the battery but do not power the device on.
- Hold down the Volume Down button then press the Power button. Hold the Power button for 2 seconds and release it without releasing the Volume Down button.
- Your phone will boot into boot mode.
- Follow the instructions on screen to navigate through the options.
- Choose "Clear Storage" (sometimes named 'Wipe Data / Factory Reset')
- Confirm your choice and wait for the device to do the rest of the work.
- When the device reboots, follow the on screen instructions to setup your new device.
After you reset the phone, and you have it setup again, if the text messages still aren't coming in then the issue is on Verizon's network itself and you will need to go into a store and show them you reset the phone and your account needs to be checked.