Many other substantive law issues arising under federal law are also considered in state court (e.g. the effect of a bankruptcy discharge in a state law debt collection action). (law.stackexchange.com)
There was concern on the part of some owners over how Navarro made his money — a piece of it was in debt collection — and a case he settled in New York in 2014 over «repeatedly bringing improper debt collection actions against New York consumers.» (si.com)