Jumpplus Portable V8 Car Jump-Starter

I bought one of these in the drop last fall as a gift for my wife. Charged it up, checked it out, and put it in her car. About a month later we had a power outage so I decided to see how it works with small electronics. Took it out of the car, fired it up, and...dead. Charged it up again, tried to charge a cell phone a day or two later and... dead. I contacted Massdrop CS to see about getting a replacement and was told there's no warranty for this product. Even after I sent a photo of the user's manual that clearly states there is a 12-month limited warranty, I was told Massdrop wouldn't honor it. Based on my online research this appears to be a Chinese-made product sold strictly through resellers like MassDrop and Amazon, so unless someone out there knows how to contact the manufacturer (Massdrop's CS advice was to " suggest trying to find the manufacturers information on your own and see if they will validate the warranty for you), then I'm the proud owner of a $60 door stop.

The one I use on emergencies for a 3.0 V6, 2.5 V6 and a Toyota LC200 Diesel 4.5 V8 (for startup uses two 110Ah batteries!). I recharge it every 8-10 months. https://www.amazon.com/NOCO-GB40-UltraSafe-Lithium-Starter/dp/B016UG6PWE/ref=sr_1_1_sspa?ie=UTF8&qid=1547396316&sr=8-1-spons&keywords=NOCO%2BGenius%2BBoost&th=1