You need a certified arborist to look at your tree. Tree services are not necessarily current on tree problems. They make their living pruning and removing trees.
Have you checked some of the outer small branches (twigs near the ends) for green under the bark? You can do this yourself, just by scraping a tiny bit of bark with your thumbnail. If you see green under the bark the tree is still alive. If not, or the twig breaks off too easily that branch is probably dying. Move further in towards the trunk, doing the same thing until you see green tissue under the bark.
It really needs some leaves to pop out soon. Have you had a lot of rain recently? I'd be watering it extra if you are in the heat wave area right now. Don't forget a tree's roots are way out beyond where the branches reach, so don't just water the tree at the trunk. A deep soaking all around it might stimulate it to put out leaves if the weather has been dry.
I hope your tree survives!
