I definitely understand the significant role our messaging services play in our day-to-day life, and it would be difficult to be happy with anything that's not working.
Allow me to gather some clues to turn this experience around.
In step 2 of this link, there is a portion that states "Text Online" https://www.verizonwireless.com/support/knowledge-base-217522/
Clicking that what do you see?
Also, you mentioned that you work in a location with limited coverage. Has the service there been look into before? Is maybe Wi-Fi available there?