You're right. The security deposit statute doesn't apply because there was no security deposit.

However, leaving damage behind is a breach of contract and Florida gives an aggrieved party 5 years to sue for a breach of a written contract.

That means that there is nothing wrong with sending you the bill 8 months after move out.

If the charges are spurious, you'll need to challenge them. If you have any defense to them, respond to the letter with your evidence and see what happens.

If you have no evidence, then it's up to you if you want to pay the bill or ignore it and take your chances.