Am I responsible?

Basically, as an owner of a dog, you are responsible for material damage caused by his behaviour, in many countries. That being said about the owner of the dog.
However when you lay a cell phone near the edge of a swimming pool you are about asking it will fall into the water, so a lack of taking good care of personal belongings is @stake.
It should be interesting to find out there's any kind of jurisdiction on a case like this, though jurisdiction in the States or Europe does not mean it will be considered accordingly in the Philippines. Since the phone is still working, I don't understand why the owner wants to get money. I should say not one single peso.