Employment Law Questions? Ask an Employment Lawyer.
Hello again and I am sorry to read about your employer's decision, I presume, to take the chargeback of the old commission, out of your bonus. Unfortunately, this is not a statutory issue, this is common law contracts. In other words, I cannot point you to a neat statutory citation for you to give your employer. You will, as I mentioned previously, have to sue the employer for the money you believe they owe you. This will be a contract action. In other words, you will use the terms of both your commission agreement (where there was, I believe, no mention of chargebacks like this) and your bonus agreement/language to show that it is not discretionary. The court will then make a determination on the language of the documents in front of them as to whether either or both allow a deduction for this.
Depending on how much you are owed, it could be. If you are owed is $5K or less, you can file yourself in small claims court, which is not expensive and does not take a long time. You can find out more about that by going to the following link: http://www.mobar.org/uploadedFiles/Home/Publications/Legal_Resources/Brochures_and_Booklets/small%20claims.pdf
As for a wage claim with the State, that information is at: http://labor.mo.gov/DLS/General/complaints
As mentioned, this might not be a claim they would take if they stick only to minimum wage claims or cut and dry easy to calculate earnings issues.