Golf ball marked "on the green" by mistake - lifted and it was off
I know that if any part of the ball is touching the green, you can mark it. Today I had a ball that appeared to be touching the green. My competitors agreed it clearly looked to be touching the green. I marked and picked it up and discovered a tuft of grass under it that could not be seen. This was a fringe anomaly, not following the defined cut line. After the ball was marked and lifted it became clear that there was no way it was touching grass cut to the green height.
What is the ruling?
This was match play.
If it was medal play would the ruling be different?