HDB Financial Services — regarding cashback of my money

I have taken a home theatre last year. Hdb finance employee said to get the emi in our finance so that you will get the cashback. After one year completed i have taken washing machine in same finance at that i asked for the cashback of my home theatre they said the amount will be credited to your account next month but its been 6mon i didnt recieve cash. I have contacted the person who gave me the finance but there is no response from their side. They are cheating us by saying there is a cashback. But they are completely cheating us please don't go for hdb finance.