If you are being paid on an hourly basis, then unless you are a doctor, lawyer, teacher, some forms of computer professional, or something of the sort, then you are non-exempt.

If you are non-exempt, you must be paid for every hour that you work and time and a half for every hour over 40 in a work week that you work. You have no legal expectation of being paid for any time you do not work.

If you believe that you are being paid incorrectly, contact your state DOL and file a complaint.