Every person engaged in the State of Alabama in the furnishing of utility services shall add to the price or charge for such utility services to every purchaser thereof an amount equal to the prescribed percentage of the gross price or gross charge therefor and shall collect said amount from every purchaser of such utility services. It shall be unlawful for any person furnishing utility services to fail or refuse to collect from the purchaser the amount required by this section to be collected, and it shall likewise be unlawful to refund or offer to refund all or any part of the amount collected or to absorb or advertise directly or indirectly the absorption or refund of said amount or any portion thereof. The provisions of this section that the tax herein levied shall be collected from the purchaser shall in no way relieve any utility of the tax herein levied; nor shall the inability, impracticability, refusal, or failure so to collect from such purchaser the amounts provided herein relieve such utility of the tax herein levied. All taxes paid in pursuance of this article shall be conclusively presumed to be a direct tax on the purchaser precollected for the purpose of convenience and facility only.