Sec. 502. (1) After installation and commencement of operation of a 9-1-1 system implemented under this act, a public safety agency serving a public agency or county within the 9-1-1 service district shall cease to function as a PSAP or a secondary PSAP 60 days after giving written notice to the county clerk. Within 5 days after receipt of the notice, the county clerk shall forward the written notice to the service supplier. (2) Notwithstanding any provision of this act, any costs incurred by a service supplier for equipment removal or system modification necessary for a public safety agency to cease functioning as a PSAP or secondary PSAP under subsection (1) shall be paid directly by the public safety agency.