We have the unlimited plan, we are only the second day into the new cycle and have not used very much data at all. So we know that the problem is not from an over usage of data. We still have 4G. We also only have one primary connection to the jetpack and still it is being so slow.
Yes, you fix it by doing one of two things:
1: Go do something else that doesnt require a jetpack/Internet access until day one of your next billing cycle. You jetpack is worthless until then and there won't be any streaming going on, most likely including audio-only streams.
2: File a complaint with the FCC. Verizon Executive Relations will email you back. This is your opportunity to get what you need. They may be able to facilitate a return, credit etc.
Basically, you've been lied to, swindled, bait-and-switched. Good luck in whatever you choose to do.