IMO, the main clinch is that they make an instrument that reacts in some way to the surroundings, then claim that it measures a hitherto undetected force. This is basic woo-woo'ism.
From what I can glean from the schreds if technical information, they have built an oscillator with a low stability and are allowing it to be strongly influenced by outside objects. Such a device will be susceptible to a number of known factors, like capacitance, inductance, noise sources, temperature. These factors are more than enough to account for any readings they get. On top of that, the instrument has several manual adjustments, all uncalibrated, but ranging over several orders of magnutide. This means that there is absolutely no way the readings can be used for anything at all. Not even measuring the known factors that influence them.
Such people are an insult to the technical and scientific community. They are either completely deluded or deliberate swindlers.
Hans