Definitely sounds like a school to avoid. In fact if what is written about it is true, it should be blacklisted and, if possible, reported. Shout it out! In all probability it's an illegally run private school and could possibly get shut down.
Either way, whether or not it's even a semi decent place to work, I would never advise anyone to work and/or live in Dongguan or anyplace near it. Very, very polluted. Dangerous place to live and breathe. Yeah, I'm sure there are more polluted places in China - even excluding Beijing from the list, but even still, considering that there are so many options, why bother with Dongguan or anyplace like it?