Instruct: Classify a given review into positive or negative sentiment.
Query: Frustrated and disappointed

I have purchased many products from Amazon.com. This is by far the worst product experience I have had. The engineering of this unit system was either done for the 1% of the population or the product was designed to fail. The detailed options do not include: answer, talk, hang-up. You must use hold, intercom, redial, etc., and then the back-lit face on the handset goes blank. It is so bad that NO ONE SHOULD BUY THIS ITEM, and Amazon.com would be wise to stop offering it.Two cans and a piece of string are superior to this failed promise.