Who’s responsible, Roofers or Masons?

[Ceair Stonge]

Hello,

My sister & i are working together to fix up our Dad’s house to sell it. It needed a lot of work. We used a contractor, a friend of my sister, and he hired roofers. While installing the new roof, the roofers damaged the chimney. They finished the roof and we found a masonry company to come out and tear down the old chimney and put up a new one, (with the help of homeowners insurance). 
The chimney is finished and now there’s a leak inside the house dripping onto the mantle of the fireplace. I called the masonry company and they said it’s because the roofers need to come back out and finish installing the flashing. But, our coNtractor friend says the masons should have done that. (The masonry workers also scratched up the wall inside by the fireplace and said it was just a touch up and our contractor should take care of it). 
I’m looking for a second opinion on who’s responsible for fixing the leak. Any help is appreciated!