As soon as you decide who is doing your local, state and federal tax returns (internal tax department or external CPA firm), give that designated person a power of attorney so they contact and speak with these governmental agencies as soon as problems arise.
Customer service personnel at these agencies have been trained not speak to anyone other than the taxpayer unless a signed power of attorney has been received and been recorded for that taxpayer. Send the POA to the authorities early in the tax preparation process. The preparer needs to call immediately when the company is sent past-due notices, or error reports concerning tax returns or tax extension requests. The more quickly they can discuss and resolve issues, the more likely additional costs or fines can be avoided.