Use caution when seeking informal tax counsel

Last month we were about to sell a new product at retail and were uncertain whether the sale would be subject to excise tax under Internal Revenue Code Section 4051. We needed an answer quickly so we called a local Internal Revenue Service (IRS) agent several times and left messages. The IRS agent never returned our call. If an IRS agent ignores a request for advice on whether a certain sale is taxable, can the IRS subsequently find you liable for the tax?