Does time really exist? or is it a human invention and convention? What is the truth? are there time particles? please remember, I'm looking for constructive answers, not condescending and void ones.
There are physicists who have said things about time not existing, such as Julian Barbour. This is a sensationalised way of describing an idea about physics that may or may not be true. It doesn't mean that there are no clocks or that clocks don't measure anything. Rather, it means something like this. If you had the complete series of configurations for all the objects and fields in the universe, at each time but you didn't have the time labels for those configurations there would be a way of arranging them in a series because the contents of configurations with very different contents would be farther separated in time than those with similar contents.
For more on this idea see