I don't know how much of it qualifies for the official legal definition of fraud, but they were definitely abusing the system and attempting to trick people into doing something that didn't make sense. For a while there they were heavily promoting *free* solar panel installation to homeowners in Ohio, for crying out loud, which is absolutely crazy.
The "free" thing would not stick in court, assuming it means "subsidized with your tax dollars", which, while technically not actually free according to any reasonable economic model, looks sufficiently similar to free to not trip over truth-in-advertising laws. If any of them were advertising free and then actually charging people, I haven't heard about it, and that seems like the kind of thing that would've provoked some negative publicity if it were happening to very many people. So while yes, it's deceptive, I don't think they're going to get into any serious trouble over that one.
If you've ever lived in Ohio, you know it's dumb to install rooftop solar panels here. We get less than a thousand hours of direct sunlight a year, sometimes considerably less, and we get a lot of the kind of up-and-down weather that is really hard on stuff installed outdoors. Those panels aren't going to last long enough out in the elements, on average, to adequately compensate for the environmental cost of manufacturing them, let alone the monetary cost of installation, and nevermind about the opportunity cost of what better things could have been done with the money. Note that this reasoning would not apply in all parts of the country (e.g., rooftop solar panels do make sense in Arizona[1]). But again, convincing people to do something that's more trouble than it's worth, isn't illegal in any jurisdiction so far as I'm aware.
So yeah, there's stuff going on that's less than 100% honest, but I don't know if it's legally actionable fraud. Perhaps not. And perhaps it doesn't matter, because at this point, most of the people who were going to be taken in, have been, and the market is saturated, and the fly-by-night solar-install companies are going out of business. Which is likely a good thing.
Footnote 1: If very many of the people with solar panels are using the public power grid as a giant free energy-storage battery to get through the night, something will have to be done about that, because it significantly exacerbate's the power company's "peak hours" problem, which is the main issue driving the continued need for fossil-fuel-driven power plants. The most obvious solution to this is to value power at different rates at different times of day depending on demand; in the past meters were too simple to allow for that, but I think it should be possible now, and in principle it should either motivate panel owners to install storage capacity in order to sell at high-demand times, or else help pay for such infrastructure on the power company's side (assuming the prices being charged at high-demand times are high enough). In any case, this is a separate issue from the cost of installing the panels and the question of how that is being funded and whether it is legitimate and above-board. It can be addressed separately, and presumably will be if the amount of abuse-the-grid-as-a-battery activity grows too large and becomes a major issue for the power companies.