Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Extremely Poor Quality

I received this in the mail, and I am extremely disappointed with the quality. The cards are flimsy plastic that one can see through, which is a problem when testing vision. The print is blurry which affects vision. As an ophthalmologist, nobody should be using these cards, not med students, not nurses, and especially not ophthalmologists. They are of very poor quality and highly unreliable. My mistake, I guess you always get what you pay for.On another note, the shipping time and packaging was perfect. Unfortunately that doesn't help the product quality.And one more note, I contacted the seller, and they immediately (within a minute responded and offered a refund). Excellent customer service. (But again, unfortunately that doesn't help the product quality.)