Deductions for painting expenses

Dear All, We had rented out an apartment in thane for 22months period with one year lock in period. We have completed one year of stay and after that we gave a month notice to owner for vacating. The owner had a broker who takes care of her property (Broker not assigned legally). So on the day of vacating the broker came to visit the flat and checked. The walls were scribbled by my two year old child other that that there was no damage to any of the property. The broker said that they need to do a complete whitewash and will deduct the full amount from my deposit amount. We debated that we will only pay on a pro-rate basis as we have paid rent for the one year period. We would like to know if the pencil and pen scribbling shall be deducted 100% of the cost of repair from us. Or we need to pay on a pro-rate basis, if so how much we are legally bound to pay. Also that the landlord mentioned that we have to pay for the full month of the contract period if we vacate. our contract started on 11th October 2016 and we vacated 26th Jan 2018. Is it right that they will collect rent up to 10th Feb 2018. Please advice and guide