I keep sharing the post to facebook but am not getting the 500xp credit. Any idea how to fix this?

I received the credit just by clicking the 'Tweet' button. The webpage was blocked, but I received the credit anyway.

I would say just wait; it can take awhile.

I had the same thing yesterday - but I remembered past sales where it took awhile.

Today I log in, and BEHOLD, the credit is there.

So, just wait awhile.. Give it a day..