Instruct: Classify a given Amazon review into positive or negative sentiment.
Query: Worked fine intially, but it didn't last long

The numbers are clear even at night however after just 5 days of operation, the green back light died so I can't see anything at night. The meter still works so I can only use it during the day. I called their tech support and said that they'll replace this one if I return the faulty unit, however, I have to pay for the shipping! Since their product failed, I believe that they should be the one handling the return cost. Returning would already cost half the price I paid for this item.