I have tried countless times over the fast few days to wear or save my outfit, but each time no new changes on my avatar appear nor is the outfit I created saved in the slot I specified.

I've already tried using two different browsers and cleared my caches/cookies to see if that would help but so far, it hasn't. Any idea what's wrong?

Please check out this thread: Pete just ate a quest Particularly B. under Known issue solutions. If none of these solutions work for you, feel free to create a new topic as described at the bottom of the linked thread. :)