Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: False advertising - this is a single pack, not a twin pack

There is a listing error for this item - it is a single pack, not a twin pack. When I wrote the vendor to ask about where the second cartridge was, they rudely replied that one is all I get, regardless of their incorrect listing. This error is current as of 3/13/10 - not sure if it will be fixed in the future, but until then, buyer beware.