HDFC Bank — Hold Funds in my Account Negative Balance

My salary account (In HDFC Bank) was created in my first company, since then I was using the account. In January'21 due to changes in the internal financial issues of the company, the Company asked us to open another salary account. Now my salary account in HDFC Bank has been converted to a savings account (Without informing me or warning me). I had called customer care and raised a request to close my account as I did not want to use the account and they did say that they will follow up with the request and close the account. After that, I never logged in to my account through net banking. When I logged into my account on 1st September'21 for some reason and to my surprise what I saw was that I have a negative balance of Rs. -57, 919.06 was reflected in my account. I request you to please take action against this bank. They have no right whatsoever to do whatever they want without informing the customer.