R.s. Appliances (kutchina) - Wrong information provided by the company salesman

After getting a call from Kutchina for their chimney I fixed an appointment with their sales representative on *th June'**. On that day I bought a chimney with an exchange offer. I bought the same in Bajaj Finance EMI. During the conversation, the sales representative Mr Biswajit Banik offer me two options. First one was * months EMI where I have to pay interest and the second one was ** months (* months EMI downpayment + * EMI) without any interest. So, as a result, I opt for ** months scheme with no interest. After calculation Mr Banik told my EMI amount is Rs. ****/-. So I have given him a cheque of Rs. ****/- (Rs. ***/- was taken for processing fees). After that next day, I got an SMS from Bajaj Finance where I found my monthly EMI is Rs. ****/- which is *.**% interest through the salesperson promised it was without interest. Moreover, Mr Banik assured me first EMI due will be in the month of August'** but I found later it is July'**. Moreover, now they deduct Rs. ****/- as EMI. I called Mr Banik, Telecaller Ms Lilly (who first talk with me) and even mail the company but till now they don't take the matter seriously and don't give me any solution. Their ultimate motto is to sell the product anyhow giving wrong information. I have been harassed since *th June'**.