Yeah, the article is really lacking in information.
My guess: tech-bro VC-backed start-up culture has clawed its way into every field by now. So in theory while it should have been pretty easy going for anyone selling and installing solar the last couple years, competitors might have more capital at their disposal. That in turn means faster scaling and rapid expansion (like over at Enerpal and 1komma5) as long as the money keeps flowing. Doesn't matter if you're profitable, you just wanna squeeze out the competition.
That appears to be working.
Although it could also just be Sonnen's expansion into the North American market being deemed more worthy of attention, who knows
Article indeed lacks details, but my guess would be that they bought the company in 2019 and loaded it with the bank debt from that purchase expecting that in a growing market and low interest rates the company would be able to pay back their own purchase.
But now a few years later, with more competition diminishing profits and higher than before interest rates on the loans, and suddenly it looks much less possible. Obviously Sonne will not admit to this, but such shady practises are sadly very common for company takeovers.
I'd be surprised if this business will not be taken over by another company. It seems like the problem is mainly operational, something that another company should be able fix
