Bad service at nissan gezina

I sent my car in for 150k service on the 4th of Sept 2018 at gezina and the car was in perfect condition to my surprise the car now has a water leakage that was unexplained when I took it back they claim that they also didnt damage the vehicle and I have to cover costs ive always filled my wiper water bottle without any leackage but now there is a big spill and nissan gezina is shying away from the fact that they are the ones who damaged the bottle in the first place why else would I take the vehicle back to them complaning about water spillage that is unexplained if I knew my bottle is damaged please assist as best as you can as I do not have money to.cover a damage caused by them