Email that screenshot to TL and they should give you your diamond. :\
And did it say in the pop up, also was it only on platinum or both?
Dragon Story no longer says the pop up about the Diamond Dragon through mining until Monday even though I have lost mine too! It no longer shows up on my Dragon Story......will other people check and open up you dragon story and see if it is still there for you?
I managed to mine a diamond but it never came into storage I haven't received any help or response from TL either