One week is really early to worry. It could take months to start a probate case.
You posed the following question:
How do I find out for FREE if my father had a will?
If he didn't leave the will, you would stand to inherit some share under intestacy laws in most states. In other words, your inheriting some share doesn't as much depend upon whether there was a will, but rather the terms of the will if there was one. So a better way to phrase the question is "how do I find out if there was a will disinheriting me?"
Do you know if your father left significant assets?
If so, and If they continue to ignore your questions, you could file a probate case on your own, asking to be appointed personal representative and alleging that, as far as you know, there was no will and that you want to administer the estate. That would give you the power to find out exactly what your father had when he died, and to assume control of those things