Don't buy used!

Don't buy used!
Bought a used Sony A7S, which they had rated an 8/10 condition. I brought it in as i wanted to see if i can upgrade (after 2 1/2 months use), and was told that there are 2 scratches on the sensor and won't even consider it. Yet they had no problem grading this an 8 and selling to the general public.
Shop at your own risk.