HDFC Bank — Repeated follow up no clear response or action. Interest rate issue

Complaint Details:
I paid required fee to HDFC Home Load through there own website to reduce the rate of interest in March 2021. I waited for a month sent an email to Customer.Service but they don't care to respond. AFter the lock down was over I approached bank office. They gave me two stories
1. They said they will reduce the interest rate based on the fees paid from July onwards. When I said it has to be done from April, since I paid in March. There response was shady. They said they need approval from head office. I had already lost trust in hdfc bank I asked them to send me an email with details.
2. Same day, I got a call now they said there is IT Issue very very specific to my account. They are contact IT department to get it fixed.
3. After 10 days, I again reminded them about it. Now they gave me a different story. Now they are saying we are waiting for IT Fix, if they fix it gets implemented from April and if they do it manually then it gets implemented from current month.
Question:
1. Why did they talked about Head office in first meeting?
2. Why am I suppose to pay for IT issue in hdfc bank.

I tried
HDFC Home loan - Grievance Website to log a complaint .. The complaint logging system itself doesn't work.
HDFC Home loan - Customer care number has automated response for everything, there is no way to reach to any one via customer care.

So basically, customer is left with no choice at all. They give you one choice that's it. Use it or leave it.
Clearly I have lot trust in them, planning to close the account as soon as possible with this bank.