Bajaj Finserv — Bajaj Flexi loan emi deducted although amount is not used

I have applied for Flexi Loan - OD with Bajaj. When I last gave my consent over email subject to telephonic discussion with Bajaj they told me that refund will be given till the last day they have charged the interest. Now when I had word with the guys in Bajaj they are saying that they will not refund the money. I raised a SR with them but with no avail and responding the same. Please note that I have not used even a single penny but paying interest for the last two months from my account (EMI mandate from my saving bank account). I believe this is harassment and mental torture which is leading to sleepless nights. I am feeling helpless and seeking justice from the forum. Please do the need ful