(a) Any telephone call made between two (2) points in the same county in Tennessee shall be classified as toll-free and shall not be billed to any customer.
(b) This section shall apply to all companies or entities providing telephone service in this state as public utilities, including, but not limited to, telephone companies regulated by the Tennessee public utility commission. However, this section does not apply to any telephone company which is prohibited by federal law from providing countywide service in a particular county.
(c) Nothing in this section is intended to modify or repeal the rate-making and telephone regulatory authority of the commission or the right of telephone companies to earn a fair rate of return.