Tamil Nadu Electricity Board [TNEB] — electricity wire underground is damaged

Address:

nO 23 ,MITHUNA APARTMENT ,BALAKRISHNA NAGAR ,VELACHERY (NEAR VENUS COLONY, Chennai, Tamil Nadu, 600042

I live in velachery and yesterday there was power shutdown till 5.00pm. When current came only our flat was not having power, so we call ae and complained today morning the line man came and checked, he said some wire has burnt underground needs to be change and asking us 20, 000.
My question is if the supply wire is damaged should we pay and repair it and 20000 is a huge amount.