Free will must be defined.
The will is governed by the disposition; i.e., what one prefers.
Absolute free will is the power to make all moral choices, including the choice to live a sin-free life.
Adam had that power and chose to do otherwise, now no one has absolute free will, the power to make all moral choices, as in a sin-free life.
Since the fall, free will is still the power to choose, without external force or constraint, what one prefers.
And now that is the rub.
Because of his fallen nature, man prefers self over God.
Nevertheless, predestination does not violate our power (free will) to choose what we prefer.
For God works within the predestined to give them to prefer his will, and that being what they prefer, their choice of his will is, therefore, a free choice.
So there is free will--the power to choose what one prefers-- in a world that is already predestined, because God gives them to prefer it.