Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Amazon can sell you invalid cards and there is no refund!

Be warned. I found the hard way! Purchased $25 T-Mobile Refill Card a month ago. Tried to use it today, T-Mobile rep says the card is void. A call to Amazon rep and here is the response: Prepaid cards are non-returnable, non-replaceable, non-refundable. Amazon will take your money and has no obligation to show anything for it. Consider yourself warned. I am not buying any cards from Amazon again. Full me once, shame on you....