Incorrect charges ruinedc CIBIL score

My CIBIL score is very less due to the incorrect charges on a credit card, which was undelivered to me and returned to the bank. When I checked with the bank, they agreed to waive off the charges but say they cannot do anything to get my CIBIL score corrected. I applied for home loan and because of less CIBIL score, I am being charged high interest rate. When I mentioned the same to bank, they say I have to improve my CIBIL score on my own. I would end up higher interest rates for every loan I take now until my CIBIL score is improved. Bank is not taking responsibility for the damage.