I've been screwing around with the JCal Pro extension since 2008 and it simply does not get better. Every so-called "upgrade" is a BIG step backwards. My clients are angry and I am exhausted trying to make JCal Pro work. I don't mind paying for it, but it should be free considering what a hassle it is to use.
What really gets me upset is the amount of time I spend troubleshooting, writing in the forums, testing, re-installing, backing up, wiping out database tables specific to the extension per customer support, and then being treated like I have installed the component incorrectly and don't know what I'm doing.
JCal Pro should not even exist. If they can't get it right they should just go away and leave us alone.
I'm sorry for your experience. We'll happily offer a refund if JCal Pro does not suit your needs.