Sorry to hear you are having trouble. Every once in a while something goes odd with the uninstall process. The first thing that I would do is generate another code for today (the code is only valid for 24 hours) and see if you can uninstall the program today. Also verify that the date/time is correct on your computer, because that is how the program determines if the code is valid or not.
If the issue persists you can try running this tool and see if it resolves the problem.
let us know if you need any further assistance