It seems to be back now, not sure if I was paid for the time it was not displaying but I think it might have. I know my miners seemed to continue working.
Are you sure it is OK now? I am trying to access it from Europe:
http://kotopool.work/
and page is still down.
Regarding your question - just see your miner's historical graph when you click on it and you will see if you have mined during the downtime. If mined (which I highly doubt), you will be paid for sure.
not http://kotopool.work/
just https://kotopool.work/