Citibank — Credit card closure- Extra charges

I converted my savings account into an NRO account. The conversion leads to close my credit card. Since I wasn't aware of the pre-closure charges, I was waiting for the March month statement to clear off the dues. From March 5 until March 20, I received no message or email about the pending charges or any communication I have to pay immediately. Also, the linked credit card was removed from my account. So I was unable to check the charges. March 20, I received a bill with almost 11 thousand extra charges (over-limit, late fee, and GST). I called up the bank executives and never resolved until one of the executives on April 18 told me that she would assist with the charges in 24 hours. She told me to hold the payment as reversal will be difficult. Meanwhile, I raised a query, wrote to the head office as I got no update in 24 hours.
On April 20, I get a new statement with extra charges, late fees, GST, and the due raised from 4, **, *** to 5 **, ***. If the late fees and GST of last month were reversed, I could have paid the due, and it would have been an end of discussion. But I got no email or notification about the reversal. And I realized the Citi bank system has a big-time communication gap and a way to make money from customers like us.
After seeing extra charges, I kept calling and requesting a solution. I would have called 50 times until today. Below are the responses from the so-called Citi officer.
• Mam, I am really sorry for the inconvenience.
• Can you please repeat the issue before I transfer your call to the supervisor? They disconnect phones when they don't know what to do. Since it's pandemic and the team is working from home, there is poor connectivity and benefitting.
• When I request them to connect me to a supervisor, as I have called them so often, they will say mam line is busy, and we can't connect you to the supervisor. However, our supervisor will contact you, which never happened, including today.
• Listen to everything and disconnect the call.
• Transfer me to the saving account department, and they transfer to the NR account. NR account transferred me back to the credit card account. SO back to square one after 1.5 hours of the call.
After so many requests, the supervisors called me Twice and told me they would revert with the resolution. Not a single time in the last 60 days, I received an email or a call with a solution. Still, I got emails from the collection team, promotion emails, referral emails, and action emails if I missed payment to torment me mentally.
After all this, I reached out to a lawyer to discuss all the issues and thought to pay whatever the bill is so the lawyer can take care of the extra charges charged to me.
I transferred money from my western union and send it to my domestic account. From a domestic account, I transfer it to the CITI NRO account. I could not make a payment, so I resend money from the Citi NRO account to my domestic account. I do an NEFT transfer from my domestic account to pay my Citi bill, and I get a reversal, and NEFT is canceled with a message" account doesn't exist." I call their executive to get a solution for this, and she told me if I could make a bill desk payment but never bothered to check why the payment was failed. She suggests I make a bill desk payment, and if it's a success, the bank will receive payment in two days. So, I make the bill desk payment for 1*** as a test, and since it was successful, I paid 5, **, *** on May 6. As highlighted above, I don't get any notification from the bank, so I called Citi bank after two days, and I get to know a different thing. The card is tagged as an NR, so payment failed, and it is reversed to my domestic account. So basically, back to square one. I would not have been able to make the payment last month as well as my card is not linked to Citi NRO, and the bank doesn't accept the payment in any other form. Now I have got my NRO closed and sent the KYC document to untag cad, but they are taking time and not reverting with the solution.