Correctly identifying if the customers are going to pay their bills or run after two months without paying, leaving a bill of ~1000 (consider that the State justice system doesn't work and the customers are individuals).
I maybe wrong but some people in my team were building a Customer HUB at a point. My understanding from the project was you could buy third party data to help you out with this.
Do you report them to any credit agencies?
No, because they can sue me if I do and even if I'm right I don't want the risk of having to pay an indemnification, Brazilian judges are crazy.