Instruct: Classify an Amazon review as either positive or negative.
Query: great - until it stops working

We're on our 3rd Rowenta Effective DX1900. When these models work, they're great. But after paying a decent amount of money for it, I expected it to last. Now on our 3rd replacement, we're getting rid of it. The safety auto-off switch is defective, and it keeps turning off every 10-15 seconds. I used to be able to shake it violently to make the auto-switch turn back on, but now I have to unplug and plug it in every time. I tried calling customer service, but they were totally unhelpful and wouldn't own up that they are selling a defective product. As I told the rep, I'll never buy a Rowenta product again.