Another way to make money

This sounds like something I looked into a number of years ago. I got a number of courses all from the same company. One was how to check telephone bills of businesses and find out how they were overcharged (they usually are due to the complexity of the systems) you would get 50 percent of the refund. Which could be thousands of dollars. Another course, one of my favorites, was to check businesses for mistakes on their rental agreement. For example they might be paying rent for 5,000 square feet. You measure it and its only $4,500 square feet) The business gets a refund that could go back for years of rent.
It goes on and on. One company specializes in auditing bills from major law firms.
As you might imagine they get refunds up to a million or more.
There was story in the news a few years ago about a black church that had been paying taxes that should not have been applied to them. They got a
6 figure refund. I remember in the area I used to live in New jersey it was decided that the rent that commercial renters were paying in that area was wrong and that they should get the money back they had paid on it.
Now imagine how many business owners did not know this or had moved and were entitled to this money. This all relates to my post on unclaimed funds.
I find it fascinating because there are these huge sums of money out there
just waiting for people to collect. IF they knew.