trying to access the RTN menu in my zte zmax pro

[Bow2Deathwish]

I tried typing ##786# and that didnt work. I also tried to access the hiddenmenu but i cant find it. i keep google the answer but i just cant seem to find any thig to help

 

[Bow2Deathwish]

really im just trying to figure out if the phone i got was referbished.