Landscaper accidentally cut off top of palm tree and then trimmed it back with a chainsaw on the trunk Will it come back to life or will it die?

Answer 1: There's nothing to be done. The remaining fronds will eventually turn brown, and the whole plant will die. Even Buddha in the Vinaya knew that if you cut off the top of the palm tree, it will not grow back from the roots.

Answer 2: It depends on which type of palm it is.

Some can regenerate from the root ball or base of the trunk. Leave it until the following summer and get a different landscaper.