Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: I got ripped off

Overall, I lost $20 on this purchase because the manufacturer - Encore - did not provide the key to install the cd. Their customer support is non-existent - no phone number - just an email address. I was lucky to receive a cryptic email response back telling me to send back the CD, however they still have not provided a return address. Urrghh!