Sue Bajaj Finance for charging interest on an interest free loan.

Hi, I took an interest free Consumer Durable loan from Bajaj Finance in the mid of September 2015 and I was informed that there will be no interest charged. When I checked the online statement I found that there is "Future Interest" Charge of INR 6.00 on the account. As I am a Muslim my religion has forbidden me from interactions which involves interest. So, I thought of calling them to complain however I found that they do not have a number to call and rather we have to send them an e-mail and they would reply after 48 hrs. I wanted to ask them to remove the "Future Interest" charges. I raised a complaint where it was dealt by the first level team (wecare team) and was informed that they can not help and asked me to consult the second level which is grievance team. I sent an e-mail to the grievance team and waited for 48 hours to get a call from them. The person who spoke to me said that the 6.00 Rs is an adjustment as it was charged extra. I asked why there was an extra charge and if it is an adjustment then why does it show as an Interest and not an adjustment. I was told that it is the way the system is designed. I was then asked to escalate it to the 3rd level. I escalated the matter to the third level on the e-mail I clearly mentioned that I want a call on my mobile after 5.30 PM on the said days and rest of the time on the office phone numbers. Knowing this they still called me on my mobile phone during my working hours and have just called once in the evening where I missed the call but the second call was not attempted. The call was made to my mobile phone the second day as well so obviously I missed it as I was in the office and the phone is not allowed. I am enraged with all of this and take this as a religious forbearance. I have gone through mental agony and have wasted precious time in sending e-mails to them without any resolution. I want to sue them OR ask for a compensation from them. I want to ask for an all inclusive interest free home loan from them. Please guide me further by suggesting an action plan. Your guidance is highly appreciated. Thanks. Faizan Rakhange. E-Mail :