Email offer 50% of scam or

[PotteryByKenda]

I had a buyer leave feedback and said she received an offer of 50% off her next order from me.  I DIDN'T make this offer or send such and email. 
WHAT IS GOING ON?
This is concerning one someone is scamming them or 2 I’m being taken advantage of.  I checked my ads sales discount and the only one I can see that I have in place is 10% for abandoned carts.

[SimplyInvitingLLC]

Maybe she ordered from another shop at the same time she ordered from you and mistook another shop coupon as yours. I wouldn't worry about it, but if suddenly you get an order that uses a 50% off coupon, THEN you'll need to investigate.

[PiecesOfMePaperCraft]

Just tell her that you have no active 50% off coupons and leave it at that. It might be a simple mistake on her part or she might be trying to sweet talk you into giving her 50% off.

Edited: I missed the part that she mentioned the coupon in her review. That makes it even more weird. 

[mommawhazelsquilts]

Maybe the coupon was sent by someone who noticed all the infringement in your shop.

Your customers can actually order something and get it for free if they are really smart.