There shall be no liability upon a supplier for erroneous collection of, or failure to collect, such tax as a result of a good faith mistake on the part of the supplier. A supplier shall not be liable for any such tax billed by it and not paid by a purchaser, nor shall a supplier be required to enforce collection thereof by means other than the rendering of a single statement therefor by its normal billing procedure.
(Ord. 7-12-71.)