In the context of spaceflight, a satellite is an object that has been placed into orbit. A few of these satellites are balloon satellites. These are satellites that are inflated with gas after they have been put into orbit. Other human-made objects are also called satellites, only placed at a much lower altitude and with a very different operating method. These are, in fact, regular high-altitude balloons but providing services traditionally provided by orbiting satellites.
Flat-Earthers deny satellites’ existence, and after they discovered the existence of balloon satellites, they started to use the fact as “proof” that orbiting satellites do not exist. It is a fallacy of proof by example. By the same “logic”, we can use the existence of trucks to “prove” buses do not exist.