Which .Gov entity to possibly take employer pay/benefit fraud to?

Not sure if I have something that should be reported to a state agency, or what, but as far as I understand it, since April, I'm missing what should be combined a few thousand dollars in contributions.

So while I've loved supervision with my company, the HR has been non existant and sketchy forever. Our pay checks are a smidge better but still somewhat unreadable on where our money is actually going. We receive normal hourly, and used to get an additional straight cash health and wellness meant to pay for you getting your own insurance. Then under ACA it became fully funded health insurance with a little leftover for 401k , and if not on insurance it was pure 401k. Something like ~4.75/hour. (and about 1.50 or something like that goes to 401k when you have the insurance.)

Early this year, they changed up their physical and it was getting a lot of guys fired including ones that are gym rats. Doesn't matter but morale of the story is I was out for a month before resuming work. Because of that my insurance was dropped. Now I figure that's ok as I havn't needed it really, and all the extra 401k money is nice, especially since I'm changing jobs in October. However as part of trying to get things sorted out before changing, I went and got into my 401k website. (Our money goes to a benefit coordinator company then to the 401k/insurance) Contributions look like a hot mess with dates randomly out of whack, and payments kinda all over the place. I showed a month of no contributions as it should when I was out, but then when they resumed and I was back to working full time, the numbers are half or less than what they used to be. (I was on average taking a day off every week while doing other job application stuff.) However, even losing a day of paid time off, with no main insurance coverage I would think the contribution from being pure 401k money should be much higher.

Sorry if it doesn't make sense as I'm over my head and it's hard to explain everything here.

As an example, here's last months paychecks to compare against what I see in my 401k. These checks are actually larger with some training pay they were weeks late getting in checks as well as some OT. Months since april working full time yet such smaller contributions??

I was never rehired just resuming work after a few weeks off. My insurance is still terminated since april. Hr lady on phone claimed i had some lesser coverage until it rained but i have no documentation dott that and they failed to ever follow up like promised. I had let the issue slide as i was told the money should be going to 401k minus maybe some if vision etc continued to be paid or something.

Nearly 5 an hour h&w is like 700 a month iirc, and the 150 is about right for the months previous to april for what we were told was leftover after paying the premium.