CROMA STORE - Charged more through EMI

I purchased an LG Refrigerator from Croma, Kormangala Branch Bangalore on **-**-****.(Invoice No SLA************). While negotiating for discount we were told by their sales person that if I opt for EMI option, they would give us Rs**** additional discount. I opted for that but when I paid my first installment I realized that I would be paying more than what I was promised. When I contacted the store they assured me that after * installments I would get the refund of excess amount.
I believed them but after paying all the installments I ended up paying Rs**** more than I was supposed to pay. I was supposed to pay Rs***** but I paid Rs*****.

When I tried to raise a complain with Croma they did give me a Request Number but surprisingly without giving me any explanation they messaged me that my request has been resolved.
I continued to pursue with the store as the centralised Customer Care refused to do anything. Their accounts department asked for details which were duly given by me but they did nothing.
One accountant said that this is the interest amount but I was told clearly that except some file charges which may go upto Rs*** I would not have to pay more than Rs *****.

Now they are not taking calls. It is difficult for me to visit the store again and again.
Please take note of this and do the needful. These kind of false promises are tantamount to cheating.
Thank you
Kiran Bothra