HDFC Bank — bank account negative balance

Hello. My hdfc salary account was converted to a savings account in 2019 when i left my job. I was unemployed since that time. Recently i got a statement from hdfc bank and thought of checking it. So i registered for netbanking and found out that my balance was negative. It was -4036rs. Because i didnt maintain the minimum balance. Now i cant close the account not can i use it as future salary account because of the negative charge. I also have a hold fund of 4036rs. Why show negative charge when i have 4036 as hold fund? And i saw an article by timesofindia stating rbi has issued all the banks not to charge negative balance for not maintaining minimum balance and an hdfc representative said theh dont do it. Then why is my bank account negative for not maintaining the balance. That too when im unemployed and during covid too.. Please find a solution to this..