According to the feedback, the buyer purchased an item from you on the 19th of March (Telephoto Zoom Lens).
If they purchased the item, but did not actually pay for it, the simplest way to ensure removal of the feedback is to go through the unpaid item dispute process (if that hasn't been done yet, I'm not 100% sure if you can still open one, as you only get around 30-odd days from the purchase date, however if you can open and close a dispute, the feedback should be removed either automatically, or by contacting eBay and requesting the removal).
If they purchased and the order was subsequently cancelled for any reason (whether it was paid for or not), then you may have some difficulty getting it removed as feeback usually needs to breach eBay policies to be removed in those circumstances.
Otherwise, the only thing I can suggest is to contact the buyer and ask for clarification of their particularly ambiguous feedback, with a view to potentially getting them to revise it if whatever issue they have can be resolved).
