First thing we would need to do is determine if the problem is with the local WiFi or with the VZW towers. There are a few isolation tests that could help us figure that out.
For example to test local WiFi you would need to take a look at your local airwaves. There are many free WiFi analyzer applications such as WiFi analyzer for Android. Fire up one of these guys and watch the air for a while to determine what may be going on. 2.4 Ghz has a very limited number of non-overlapping channels which are ideal to be on, if you are in an apartment or have many neighbor signals near by then 5.0 Ghz is certainly worth a shot.
To test the VZW towers you would have to travel to a different area for a while and compare your results. For example test directly outside your home or in a different area of your town. If you happen to travel out of town then test at your destination when a different tower can be used. Something that can assist you here is called a site survey.
More info on Site Surveys:
If no progress can be made in either of these areas then there's a chance the Jetpack is bad and would need to be replaced. One thing is for sure the more leg work you do on your own before calling VZW the quicker you will flow through their troubleshooting and arrive at an acceptable solution.