I did work for Vistro in September 2017- January 2018 that totaled $1,101.  They did not pay.  Over the next year, I sent monthly emails and phone messages.  Got a couple responses that the "check was in the mail".  Then in March of 2019  I received an "Echeck" for $201.  First time I received an emailed check.  It did clear the bank, but they still owe $900.  I continue to send balance statements, but I do no expect to get a response until maybe next March.   Good Luck.  ~R~

Update, as of 7/29/2019, still no remittance for the balance.