In my opinion any half decent electronic should last more than 5 months. If your thinking of replacing it with the same one, had ours since August And its "stored" on the floor of my car and still works. I agree you should contact the manufacturer.
I have had mine for over a year and is often handled by a four year old and we have not had any problems. I use it when we travel to power my tablet and do love it. I would contact the manufacture and see if they could help you.