I am a California attorney and cannot give legal advice in your state. My comments are information only, based on federal law and general legal principles. YOUR STATE MAY HAVE ITS OWN LAWS THAT OFFER SIMILAR OR GREATER PROTECTION. If I mention your state’s laws, it only means I did a quick Internet search and found something that looked relevant. You MUST check with an attorney licensed in your state to learn your rights.
Your employer is required to pay you for all time worked. An employer may not retroactively change the conditions of your employment by asking you to sign an agreement after the end of your employment or in any other way.
You can pursue a wage and hour claim with the appropriate government agency. According to Workplace Fairness www.workplacefairness.org, Florida does not have its own state agency for enforcing wage and hour laws. Therefore, you can file a claim for unpaid wages or overtime violations with the United States Department of Labor, Wage and Hour Division: http://www.dol.gov/whd/contact_us.htm.
I hope you can resolve your situation and wish you the best.
You should consult with a local employment attorney.
As I understand the law, if you are an at will employee your employer needs to pay you for the time you worked regardless of whether you quit or were fired. The employer cannot make a non-compete clause a condition for you to receive your last paycheck that you earned.