Jealous jealous

I own a preorder and ready stock blogshop which bring in stocks from Taiwan.
Business is going on quite well I must say. And I have been operating my blogshop for quite long.
But today, someone left a message on my cbox stating that she just bought a bad quality clothing from me at RM50++
The problem with that is, I recently did not sell any ready stock clothing. I checked back on my records and the last time I sold a ready stock item is 3 weeks ago with the colleagues of that customer coming to me to order more items coz of the good quality and affordable price.
And no one has ever emailed me to complain about the quality of my clothes. I can honestly say that the quality of my preorder items is one of the best in the blogospere. Many of my customers and return customers can attest to that.
So I think that it must be the work of a jealous competitor.
So sad that people would resort to such tricks to bring another blogshop down :(
And I don't know how long it has been since that message was left there for others to see :(
Why la do this to me??