Buyer Consistently Leaves Negative Feedback

[laszpower]

We discovered a buyer who has left 11 out of 15 feedbacks negative to sellers in their most recent feedbacks. It really looks like this buyer is looking for a free product or money back from the seller. They may have changed the 4 positive feedbacks after receiving something from the buyer. The buyer did not contact us before leaving negative feedback. We have a rock solid standard for customer service.

Is there any eBay mechanism that finds these buyers who leave inordinate number of negative feedbacks for sellers? Can the buyer's account be cancelled for this type of behaviour? 

Fortuneatly for us the item was not expensive and we sent out a replacement after contacking the buyer.