Due to the very general nature of your question, one of the best ways
to start is to call your state Division of Workforce and Labor, or
look it up online. To search, simply type in your state name and Dept
of Labor and you will hopefully find information pertinent to your
situation. If not, just take note of the phone number and call.
For example, here are examples from New Jersey and California.
The following articles might be of interest, though I have no idea if
they will speak to the particulars of your situation.
Payroll Mistakes Can Cost You - Big ! (Labor & Employment Newsletter -
Double Check Your Paycheck, by Sam Kerch
Aside from this suggestion, unless you are noticing some very serious
infractions, you might be dealing with a less-than-business-savy
employer who is trying to do their own payroll. In that case, you can
continue to be patient, or copy off the relevant accounting
information that is affecting your specific situation. In any case,
keep ALL your paystubs.
If the "mistakes" are bordering on criminal, I would report your
employer rather than deal with it yourself!
employer liability for payroll mistakes
department of labor (state)