Hyundai Motor India — in favor of free service the give me rs.12000 expense

Address:

New Delhi, Delhi, 110007

On 15th november i received a call from hemkund hyundai b-99, wazirpur industrial area that you ave taken some services from our service station how was your experience and after giving them a true feedback they told me that we are going to provide you free dry clean and washing of your car on which i got agree. And they done it great no problem and send my car at my home around 7 pm.
Buy yesterday at night when i start my car i found something wrong and left it over there as it is. Then today morning i again tried to start it and start driving i got to now its staring was to hard to move and i noticed it that car is showing eps light.
I called a local mechanic and he told me that there is chances of water seepage on a part so he told me its better to show it to company because its fault of company. After making a call to company they are denying that they have not used water inside but there are clear marks of water on the inner body of car.
In this way in a favor of free service or we can say because of there negligence i have to suffer a expense of around rs.12000 if they don't admit there fault which they have done before also.