Greenware is good only until you buy the product, aftersales service is crap and a total scam! I bought a Galaxy S8 from their Liberty Plaza shop around 6 months after it released in 2017 under 1 year warranty, after around 3 months, all sensors (gryo, proximity, auto brightness etc) broke. Went to the shop to claim warranty, they said that they'll give a brand new phone and asked to come in a week, when I went, they gave me a used phone in a different color that had scratches, when I demanded a new one (as they promised), they asked me to come in a few weeks. When I came in a few weeks, they said that they have a brand new phone, but when they showed it to me, it was an opened box, but since it didn't have any damages I took it home. Again the same sensor issue happened to this "new phone" as well. They said that they can't give a new phone again and will fix it for me. I didn't want to do any more business with them and requested a refund and all they gave me was 50% of what I paid.
Now that I think of it, its totally possible they gave me a used phone when I originally bought it for the first time because it had really bad battery drain, 3 hours screen on time on light use.
Lesson learnt, buy from official channels whenever possible.