Here is more information about the password recovery chances.

We accept your payment only after the password is successfully recovered. The search time depends on the PDF document version and the utilization of our computing cluster, so it may last from 10 minutes to 24 hours. You may expect a successfully found password with a 61% probability. If your lost password is not found in the free check, there is a more guaranteed option: a paid password search through 20+ billion records. You can try a free check for weak passwords: it is successful in about 22% of all cases, and it takes only one or two minutes to see the result.

Maximum upload file size: 100MB What are the Chances of Recovering a Lost Password?