How To Spot A Fake Tiffany & Co Piece Of Jewelry?

I recently purchased a tiffany & co silver heart toggle necklace off ebay. Of course, I did my research AFTER and discovered the majority of them are fakes. My item arrived and it just doesn’t look right. I’m wondering what are some of the tell tale signs of a fake. I still paid decent money for it….about 80% of what Tiffany & Co charges….. I do not live near a Tiffany so taking it to them is not possible….