No, your employer is unable to send your paycheck to the 401K administrator to deposit it into the fund. If this is what happened, you will find that the administrator will be treating it as part of your 401K, and you will have to pay additional taxes on it. Also, if the plan has a vesting rule, and you are not fully vested, you may find that you will only be getting part of the balance in the fund.

If the check has not been cashed yet, I would advise you to call your employer and tell them that you are filing a claim with the department that handles employment in your state. Request that a stop payment be put on the check, that they contact the administrator to tell them and request a check be cut and sent to you immediately.

If the check has already been cashed, I would suggest that you still contact the employer and request your paycheck, informing them that you will be filing a claim with your state department of labor.

Sometimes the appropriate agency to file a wage complaint is with the U.S. Department of Labor, and sometimes a state will handle employment claims by its own state agency. In order to determine who it is you need to call, simply Google: (your state) department of labor.

States that handle wage claims will sometimes add additional fines and penalties for each day that a paycheck is withheld.