kerfuffle, carfuffle, kurfuffle [kəˈfʌfəl]nInformal chiefly Brit commotion; disorder; agitationvb(tr) 

Scot to put into disorder or disarray; ruffle or disarrange[from Scottish curfuffle, carfuffle, from Scottish Gaelic car twist, turn + fuffleto disarrange]

Doesn't exactly mean the same as confusion, but in no way does it mean that you called him a bad business person. Tell her to look it up if she's confused.. I don't know why she didn't do that in the first place

Just block her emails and tell her if she continues sending them you'll report her for harassment

Also remind her that most sellers don't look at a buyers feedback anyway