If your company feels the insurance carrier has not billed you correctly - especially at the time of premium audit, then by all means do not wait to send in a premium dispute letter.
  Your insurance policy should have an address for premium disputes.
  Each state has its own set of premium dispute rules that may differ somewhat between each state.
   The three main concerns that we have seen with premium disputes are:  

• The employer does not dispute the billing timely.
    All states allow the insurance carrier to cancel an existing Workers Comp policy if a prior policy billing has not been paid or disputed timely.
    If you are going to seek the services of a Workers Compensation consultant, make sure you do it quickly after receiving a billing.
   
• The employer ignores the due date of the premium audit billing.
  This goes along with the first bullet point.
    In this economy insurance carriers are not very flexible if a company does not pay or contact them by the bill due date.
  
• The employer uses the dispute letter as a way to stall the bill payment.
    This may ruin the business relationship between your agent, the carrier and your company.
    Be very careful what you include in the dispute letter.
    It is very difficult to add more disputes to the original dispute letter.
   

If your company is unable to pay the full amount of the undisputed part of the premium audit bill, contact the insurance carrier immediately upon receipt.
  Some carriers will accept payments over a few months time.
  The key here is contacting the Workers Comp carrier before the due date.