Flo is being sued by ADT -- the largest home security company in the United States -- which claims in 2009 it wired up Flo's home with a system that included dozens of sensors, smoke detectors and at least 27 security cameras.
In the lawsuit, ADT provided a copy of the contract ... which was signed by a man named Lee Prince -- who is reportedly Flo's manager.
According to the lawsuit, Flo paid the initial deposit -- $19,366.66 -- but after the work was completed, he never forked over the remaining $38,733.
Now, ADT wants the money PLUS interest, totaling $47,134.40.
Here's where it gets crazy -- Flo Rida has fired back at the suit ... saying he NEVER authorized the work despite Prince's signature ... and claims he doesn't owe ADT a dime.
A judge has yet to rule.