The same thing happened to me as well with the 5-port version, and more recently with the more powerful 6-port version. I still buy and recommend their products thanks to their very responsive support, though.

I had a port die on an Anker unit that was about 11 months old - it was replaced by Amazon (UK) without any fuss + I got a prepaid label to send back the faulty one.

i was in the same boat with a charger that i bought in 2013. they sent out an email explaining that was a design fault (non-reversible current limit) and they were willing to replace/refund. i wanted a replacement but unfortunately i bought it when i was travelling to the US and they can't ship outside the US. they refunded the $20 and 2 of the 5 ports still charges fine.

It seems to be occurring rather frequently according to Amazon reviews.