37 Fla. Stat §627.6131(6)(a)(2)

(2) A provider that denies or contests a health insurer’s claim for overpayment or any portion of a claim shall notify the health insurer, in writing, within 35 days after the provider receives the claim that the claim for overpayment is contested or denied. The notice that the claim for overpayment is denied or contested must identify the contested portion of the claim and the specific reason for contesting or denying the claim and, if contested, must include a request for additional information.