Reg: Extra amount deducted and are not paying it back

Hello Sir/Madam, I had taken a personal loan from TATA capital and there was EMI deducted 3rd of every month. In the month of December 2016, I had had cheque bounce and the agent called me for payment with the penalty. As there was a demonetization effect I said him that I cannot give you a cash instead I can pay you online. He provided me the details of TATA capital and I did the transaction on 15th December with the fine. But again on 17th they deducted Rs 9500 which was my EMI amount. I immediately called the agent he gave me his supervisor number and he said it would be fixed in one week but it did nit happen. I gain called him I think after 2 weeks. He again said need to check. Later the agent and his supervisor both are not picking the call. Also I raised complaint in customer care, they asked me to send the transaction history. I sent the same. They said that my registered email id was changed. I raised a request to change the email id. Later I sent the correct details and after calling so many times they sent me a mail stating that there is no extra amount deducted and instead I have to pay them Rs900, which is the fine charged for latepayment in the Month of Apr 2016 and December 2016, where I had even cheque bounce in the month of April. I asked the customer executive when was the amount credited he said on 17 th December 2016. When was the cheque presented he said 3rd of Dec 2016. I asked him to check again close the compliant giving the 10K . So he raised a complaint again and said it would be resolved on 2 days. But when I called them after 3 days no response they always say their server is down and they don't have courtesy to listen to the issue. It is almost 4 months please suggest I am frustrated. My CIBIL score is effected now. Now my questions are as below, 1. When the cheque was presented on 3rd Dec16 , how did amount deducted on 17th Dec16.Which is agreed by the bank. 2. When I did not pay the fine on Apr2016, why did they not ask for it till I raise a concern and not even single followup was done. 3. When I provided with the transaction ID to their bank, raised a complaint why still there is no inquiry done with the agent.Also they have not provided any status on the complaint raised where I asked them to keep me updated. I have recordings of all the persons whom I spoke to. The guy who collected money in the month of Apr16 same guy has come now. And also he did not have ID card when he came at that time. When I complained. No action taken. Please suggest Thanks in adavance.