Neighbors tree is ruining my rooftop! I've talked to him about it for a couple years! I can't afford to cute it down. Who's responsible?

My neighbors tree is destroying my roof! There are also very big heavy branches over my deck. I'm afraid to sit out there. The tree is old. It's an oak tree. Who is responsible to cut it down? I can't afford it. I have one on my side that needs to be cut. I've talked to him about it for a couple years now but he says it's not his problem. What can I do? The tree is going to go through into the house soon. It's digging down on the roof.