God does not treat everyone of His fallen creatures exactly the same. He can do as He pleases! He is the potter!
Men today, are a fallen creature – due to Adam's Sin. Since that time, we are all born as fallen creatures. Why? Because our heart is not right! We are at enmity with God! As such, we are unable to please God.
Are we given free will in the choices that we make? I would have to agree that yes we were given a free will.
If I decide that I want to turn right, I can turn right because I will to do so. If I decide to go on vacation, I can do so because I will to do so. But the will is not sovereign above all things, It can only will to do things based on the heart's desire. The heart says I desire to go on vacation, then the will kicks in and the decision is made. But we cannot, (in and of ourselves), turn to God because we are at enmity with God!
So the question is, How do we get a new heart? We must turn to God, repent of our sin, ask for forgiveness, and trust that He can provide it, through His Son who died on the cross. Is it the natural heart's desire to turn to God? NO, and it never will be unless God call us to Him. Does He call all people? NO, the call is only provided to some, His Elect. Most often it takes place through hearing or reading God's word, and the Spirit laying it own our heart.
Men may argue that this is not fair as long as they wish, but scripture points to this very fact. And the result of this process is that we are changed, we are a new creature, we have been given a new heart, and our free will now works on the new heart's desires!
What happens to those who are not called? They are not God's elect unless He chooses to call them. The very fact that any are called is more than we deserve!
I do not like to be classified as a Calvinist but I also do not believe in a fickle God. If He calls us then I believe it is DONE! He will not test us more than we can bare. Do we continue to sin? Yes! Even though we are a new creature we will not be perfected until He comes again.