Ελεγκτής χωρίς ψήκτρες ηλεκτρικού ποδηλάτου Z20 PLUS 500

I bought pvy Z20 plus 500 and it was quite good but it suddenly stopped working in two weeks, I took it to bike Shop which they say it might be the controller then I order th controller from Pvy company unfortunately they disappointed me when I received a completely different controller which it's not what I ordered! And I'm still stuck in their commutation which it's only a email.