I am truly sorry you have had a problem, but not everyone has. At the end of any training sessions I was always told to put down training time, the wage for it is $15 in the invoice, and I have always been paid.
I doubt you'll take the company down. Likely you will get what you believe is owed you, any attorney fees/court costs, and MAYBE a small compensation for your inconvenience.
I haven't had a problem so far with them, but I am cautious and wary as with any MTSO these days.