What you are describing is a form of "self-help" eviction. A landlord can't do this. You actually have an action against the landlord for tampering with your breaker. Your remedy is to file an action in court. I would advise you obtain a local attorney to assist you on this. Florida law allows the reimbursement of attorney's fees if you become the prevailing party. If you can't afford an attorney, talk with your local legal aid and they might take on the case if you qualify. Also, if you hire an attorney, that attorney might be willing to take it on a contingency basis because they can go after the landlord on a multiplier. You really need to act on this before it gets out of hand.