Well we clearly observe the passage of time, does that mean it exists? This raises the question of what "exists" means.
I guess you could posit the possibility of learning some deeper metaphysical truth that paints time as an illusion, but then, what's to differentiate than deeper level of understanding implying time is an illusion from it simply being the underlying basis of time, with time still being a reality on the level at which te observe it?
It's kind of like the question of solidity. Solidity seems obviously to exist, but if you understand physics you realize that on a microscopic scale objects are mostly empty space and even the subatomic particles themselves aren't solid, they're more like fields and they don't actually touch each other, they just repel each other more the closer they get to each other. But does that mean that solidity is an illusion, or merely that it's strictly a macroscopic effect?
Another issue is that time is really an abstraction. Time is a measure of change. Change is an abstraction too, can you point to where change exists? Can you touch change? Do abstractions "exist"? On one hand abstractions would seem to be superfluous as existents given their comprising, lower-level elements or concrete referents, on the other hand any description of the universe would seem to be incomplete without mentioning change or time..