Am I being scammed? Advice please.

[klondiketradingcompany]

Hi all, I'm a new seller, just had my first sale, when I sent the Invoice to the buyer, they sent a message back claiming I had changed the listing from free shipping to buyer pays. I checked the revisions and only had one change to the description (spelling error) prior to his bids. 

what should I do in this case

Thanks in advance

[klondiketradingcompany]

Thank you all for your help, the issue has been resolved with the buyer accepting my apologies and agreeing to have the order cancelled

I will notify Ebay of the incident re: my selection of International Tracking resulting in a glitch with US buyers