So I've this GT 620 on one of my old rig. The card was malfunctioning. The standard warranty period of the card was over but I've registered the card for extended warranty long before. Still to be sure sent an e-mail to technical@zotac.com. They have asked for extended warranty registration e-mail and purchase invoice. So sent both by e-mail. They instructed me to visit their service center on 73 , Metcalf Street. 1st Floor. Kolkata - 700013. They also intimated the service center about the same. So went there with card, registration e-mail print out, purchase invoice. Service center guys accepted the card, tested it and handed me a replacement card then ( no box ) and there only. I think it's a refurb ( it looks brand new though ) unit but if it works then it's all good ( had time constraint so testing on the replacement card not done yet ). Overall the service quality is very good.