Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Labels won't stick to these inferior greasy envelopes

I bought envelopes on this advertised heading from "ValueMailers" (SELLER). They have a greasy-like substance that will not allow a mailing label to stick. Therefore I have 1000 mailers that require scotch tape to hold on the 3 labels I use when I send out my orders to my customer. I contacted the seller and they refused to pay return shipping and told me to tape on the labels like they do---so, their product is inferior.