It's a common problem, and well documented if you would do a search. Either get a Grom usb adapter, or find a used 04+ head unit.

 

I just bought my car 6 months ago and experience the same common problem. Everyone that has owned an IS300 tells me to dump the radio and get a double din. It seems like the only flaw to this car is its radio, it never worked as intended

 

No. 01-03 were prone to jamming. 04+ were redesign to be more robust, thus my suggestion to find a used one off a 04+. Once again, this is well documented on the forum. The search button is your best friend.

 

My '03 disc changer was replaced under warranty around 60k. It jammed and was doing the same thing. I still use it now at 88k mi and have no problems. I like the factory look.