For someone to portray themselves as a roofing contractor and not having a license is against the law.
The State of Florida requests that they be notified of anyone performing roofing work without a roofing contractor’s license. The easiest method of reporting is to go online at: My Florida License
Click on the link to report unlicensed activity and enter the information as you know it to be. Another way is to call the police. They will take the information or they may direct you to the local building department for a building official to come out and investigate the claim.
Don't be the one caught with the unlicensed roofer working on your roof. The building departments patrol neighborhoods in search of unlicensed and unpermitted activity. When discovered, the workers will receive a mandatory stop work order and if they don't stop, the police will be called upon. They can be removed by force if necessary whether your roof is protected at the time or not. The State of Florida is very serious about their licensing laws and do not take the disregarding of them lightly.
Help your neighbors and help yourself, always use a licensed roofing contractor.