I had a case where a TearDown Script in SoapUI (version 5.5.0, community edition) was not working at all, neither on test case or test suite, nor on project level, whereas the Setup Script was working on all three levels.
Since I didn´t find a solution browsing the web, I´m sharing how to overcome this here:
On top of the script window, there´s a green arrow to manually start the execution of a script. Simply press that button – it might fail and result in a popup with an error message, but in my case that solved the issue, the TearDown Script now also got executed after running a test case, test suite or all suites in a project
Not sure it helps in your case as well, but you might want to try it out.