Lawyer Notice to return Security Deposit

[Mohan P.]

Hi, I received a legal notice from my former tenant stating that I need to return full refund of their deposit. The property is in FL and is a Long Term Rental. I sent them "Security Deposit Refund and Itemized Deductions" that explained how the Security Deposit was used to fix items and the remaining balance to be claimed to his EMAIL ID. Never heard back from him until Today from his Attorney. Their claim is that since I haven't sent that through Written Notice by a certified mail, that I am not eligible to put any claim. Did anybody else deal with this situation? Kindly advise.