Banking details update for 25 days

I update my banking details and submitted all the required supporting documents I was told the process will take 21 days, today is the my 24th day my refund still on hold banking details not updated. I escalated the matter on Monday the 18th August even today I am still waiting. Why are you not meeting your turn around time, can someone action what they need to do I CANT WAIT FIR 34 DAYS FOR MY BANKING DETAILS TO BE UPDATED