HDFC BANK - Indiscriminate account blocking by HDFC

I am a customer of HDFC Bank, and I had requested for a change of address on my account. The process was completed successfully, but * days later HDFC blocked my account without notice. Upon many attempts to understand the rationale, I was finally told it is because their postal service partner could not deliver a letter to the new address. To note here is, I was never contacted by delivery person nor to the best of our knowledge a delivery attempt was made. Even if it was made, without calling to get directions, marking the address as incorrect is a gross negligence in India where our addresses especially in Tier */* cities are explainable and reachable only with verbal guidance.
Since then, I am unable to do any transactions using netbanking or phonebanking. Despite writing to Preferred Banking email (I am a so called Preferred Banking customer ironically), making my father visiting the branch upon advise by the bank's appointed relationship manager, writing emails and raising customer services requests, there was no resolution. I then even filed grievance complaint, yet no response on that. This has been * weeks now. Now someone from a 'central team' has been assuring a local branch staff will physically visit and verify address, but nobody from their local branch has done so or responded to calls.
I am going for higher education and in extreme need of funds, my banking activities being restricted has already created and still creating a great inconvenience. I am unable to obtain loans, or liquidate my fixed deposit to get required liquidity, or have to even face difficulty to pay my credit card bill.
Upon speaking to their customer service, they ask me to wait * more week or * more day, however this has been simply going on for a month now. There has been no urgency displayed, no sympathy, no punctuality.