Gas gauge not moving

Hi there all. This is my first post to this forum.

I bought a used 2013 Prius C from a Toyota dealership about a year ago. A few days ago, I began to notice that the fuel gauge on my dashboard didn't seem to be moving after a period of time that normally would've seen it decreasing. I thought, "Wow, this car's got great gas mileage." Next day, more driving, same thing - clearly something's wrong.

Two things to note:

1) I was recently involved in an auto accident. My car was repaired and I thought it was good as new. Most likely this accident is the cause of this problem. Now bear in mind - I drove that car for two weeks before this issue occurred, and the fuel gauge was working normally.

2) Much more minor but I just can't help but think it's related since the timing matches up perfectly. The day this started, I went to my car and noticed that the little door to the fuel tank was open, had been open all night. Not sure how I could've possibly missed this, I never have before. And I use street parking, so my immediate thought was that somebody screwed with it. But that might be a bit paranoid.

SO.

Any way to deal with this that doesn't involve great cost?
Is it most likely a sensor-related problem?

Any advice is greatly appreciated.

 

Thank you! Alright then. I'll wait for a bit and see if it just resolves, and after that I'll try the battery.

 

Okay so. I finally got around to this. Didn't go the way I want it. I remove those cheap little clamps, and now by the way I can't get them back in. Not without breaking something. I remove the panel and looked at the battery, and I have the manual open the entire time, but what I saw inside the battery did not resemble what I saw in the manual, and I was very hesitant about taking any action.

And honestly, that's how I left it. I would really be only confident right now for somebody to look at this who really knew what they were doing, particularly and reinstalling those clamps... Obviously I am quite a noob when it comes to this sort of thing, but I just don't want to screw any of this up...

There is sort of an insurance claim. The accident occurred while I was driving for Lyft, so insurance was outsourced. As for the repair shop, I don't really know what to say to the guy... It doesn't seem like it was his responsibility?

 

FYI I do a lot of dictating into my phone instead of typing, and that's why my messages occasionally can look a little weird...

 

Thank you! I feel there's no harm in asking, but I am curious about how much responsibility the body shop guy actually has... Dubious about it...