One thing to mention about the recruiting center never answering. Are you leaving messages?
Its fairly common for many businesses (banks spring to mind) to screen calls. The recruiting officer I dealt with was no different. When someone calls and leaves a message, it enables the person recieving the call to find out who the other person is (so they can get their file ready, and in front of them), and it enables them to try to ensure that you have their full attention when they do call back. It also seems to be common practice for a lot of people not to leave messages because they "don't like talking to machines". This pretty much ensures that you'll never get ahold of them.