Just to clarify - can you actually SEE the water tank (which is usually white and somewhat translucent)? I'm asking because you want to be sure the tank sensors (which indicate the tank level) are indeed working correctly. Different rig, but I can see the top of my water tank from under the kitchen sink.
If you can see the top of the tank, you'll be able to tell how full the tank really is... and actually confirm what the tech is telling you. I'm NOT doubting what the tech told you, just suggesting you "lay eyes on the issue" and be satisfied that is indeed the problem.
Here's a similar thread. Look at the pic... it shows the sensor connections on the side of your tank. Check yours and make sure they are all connected.
https://www.thorforums.com/forums/f4...ter-22986.html