Verizon still hasn’t released a working version of the My Verizon app for the HTC Thunderbolt, however the official APK was found online by Droid Life, but their link was later removed at the request of Verizon.
This is not a hacked version from some forum – it’s the official app.
You can download it here: https://dl.dropbox.com/u/11723939/MyVerizon.apk