IDFC Bank — Threatening & suspicious calls

Hi,
I've had taken an electronic device on loan and this month I was supposed to get EMI. I'd maintained my balance on the 1st oct so that the emi is cut on the 2nd. Though it didn't. After 2/3 days I called up the customer care to ask what the problem was and they said me that my EMI was bounced and the second date would be 5th oct for EMI with charge of rs. 400-500 something between as bounce charge. Why am I supposed to pay the charges if I made sure that the balance is maintained a day prior. Ok I forgot it. The second turn was on 5th and still it didn't cut and the status again showed up as bounced. Is this funny? I'm already going through alot of depression in my house and this thing is stressing me more? Apart from that I made many calls to ask what the problem is and I started receiving many calls from hell lot of numbers stating that they are calling from IDFC COLLECTION TEAM! They started bombarding me for the bounced loan. One gives me a solution, one answers my question and few minutes later the second person calls me and asks me about the same.

An person said me after alot of argument and discussion about my emi and balance maintained after I explained her whole thing .. she gave me a good solution that I maintain the balance 2days prior for safer side and this time no charges will be taken as an exception. Ok agreed to her and I was satisfied by the solution. But 1hour later again I got one call and the person says the half amount of the charges will be taken. Like seriously? This is the worst experience ever I could tell you.
Yesterday, I received one more call when I was traveling and in stress I was saved from an accident just because of my friend. If the person was not present there with me than literally anything could have happened with me. I continuosly said the person that I've already spoken to many staff of the bank about it now what's up more? And I'm traveling so cannot speak with you at the moment. The person still didn't mind whatever I said and asked me to do the payment continuosly. He still kept ignoring whatever I said him so I had to abort the call. Later, the same person (a guy) texted me on whatsapp. His name is prince. I asked him that if they guys are allowed to text personally to the customers so he said that yes if customers don't answer the call. I mean I'm pretty sure they're not allowed to do so.

Today again from morning 7am I'm getting calls and trust me I've received 7+ calls till now ie. 3pm. So irritating. I'm sick and have to consult a doctor I could show my medical certificates if needed.
The last call I picked up somewhere around 2:30pm and I was in full intention to screw this person... I said him that I'm fed up of your calls and I've already spoken to the team. He literally started scolding me and giving back answers. I said which bank is opened on sunday how could you call me up. He says we have full authority and RBI has given us this rights. I mean how do these guys have rights to personally text me on WhatsApp and call and threaten me. Is this rule by RBI? Really.
I've one of my relatives working in RBI. and he doesn't seem to inform me something like this and agree to it.

Please take actions against this and revert me about this. A kind request. I'll provide you the numbers of the people who contacted me:

+[protected]prince- the one who WhatsApp messaged me)
‪+[protected]‬ (the one who gave me RBI rule jazz and threaten me by scolding on call)
[protected], [protected], [protected], [protected], [protected], [protected], [protected], [protected], etc.

Please confirm if these numbers are verified by the bank and are genuine. I'm looking for quick and genuine revert on this case.