What is due diligence?

According to Wikipedia, Due Diligence is:

"Due diligence" is a term used for a number of concepts involving either an investigation of a business or person prior to signing a contract, or an act with a certain standard of care. It can be a legal obligation, but the term will more commonly apply to voluntary investigations.

I have seen the use of this word from a lot of individuals lately. In particular, the people once connected with Trace Trajano. For some reason, Bo Sanchez, Jomar Hilario, Larry Gamboa et al., have moved on separate business paths.
All the other individuals I have mentioned once supported Trace. Why the sudden withdrawal and cleaning of hands? Maybe they did their share of due diligence. Good for them. What happens now to the people who had transactions with Trace? What would happen to them? I am not saying that there really is a problem but for people like them to withdraw support from Trace Trajano is like biggy! The question is what happened? What really happened? 

The bitter taste.

My husband recently joined Trace Trajano's last AC (apprentice challenge). Payments were already made. Now these issues happened. To make matters worse, the same person who had influence or inspired my husband to join the challenge is also now withdrawing from the team.

Are we worried?

I am. 

Hubby? He doesn't show it.

Did we act with due diligence? I can't really say yes. 

But we acted based on trust to good people who endorsed him. Good people who I believe have no intention of fooling people. It just happened that the person they have endorsed moved to another direction. To which direction it is, I do not know. I am just hoping that whatever it is, we still get what is due for us because what we paid is hard earned cash.