Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Buyer Beware!

I would be wary purchasing an item from this seller. The sticks that I received had little or no nitrate on the stick. You can tell if there is adequate nitrate when the skin discolors to a dark brown/black. When using these sticks it turned the skin a very pale gray/white which indicated potassium but not silver nitrate. I am not surprised that they did not work for a previous reviewer. I emailed the company about the problem and they acted surprised and did not offer to replace the item nor did they discuss any refund. I shipped back the item over five weeks ago and have not received a refund or any communication from them. I will not be buying from this seller again.