Thanks for posting. I would contact them through Amazon and ask if they'll replace it. Give them a day or two to give you an answer.
In the mean time, post a low-star review saying at what amount of use time it failed and compare it to the vendor's lifetime spec posted on the Amazon description. Include in your post that you are attempting to contact the vendor to resolve the issue.
Running on all the time for 1.5 years is 13,140 hours. Most LED specs call out at least 50,000 hours life span.
Amazon vendors are very conscious of their reviews. Any time I've had an issue and followed the above protocol, the vendor sent a new light, and I changed the review and bumped up the stars to indicate that their customer service replaced the light. I've had 3 or 4 lights fail like this in the past few years.
Good luck!