Instruct: Classify Amazon reviews into positive or negative sentiment
Query: No Support: caveat emptor.

I have used PowerPDF successfully for a few documents. But when it began to misbehave in such a way as to make it unusable, I emailed the vendor's product support describing my problem and asking for advice. They told me the product was no longer in development, and they wouldn't help me. When I tried again, and again in very polite terms, I received no response at all. The price is too high for an unsupported product.