Destiny and free will are not mutually exclusive things. They co-exist harmoniously.
Whatever will be will be, and whatever will be is being carried out by the supreme energy. This force is known as destiny. But at the same time, the supreme gives us the freedom within our own destiny to make choices according to our will.
How can our paths already be destined, yet we still have the ability to act freely? Acintya-bhedabheda-tattva. Simultaneously one and different.
We are both controlled yet independent. For example, a government may have laws against killing, dope dealing, prostitution, and so many other things, yet we can see that these things are going on in a major way regardless of the law which forbids it.
So the law controls society, yet even within this controlled environment there is a little independence to do whatever we want. Similarly, in the cosmic perspective, there are natural and universal laws which are controlling the universe and even our actions, yet we are given the freedom to make our own moves and receive the according results.
Your use of your free will is happening according to destiny.
