Guys, my english isn't perfect but i make print screen tomorrow from miner and from nicehash. i think it will be better for you!
The pool graph isn't the "absolute truth". The parts of the server that generate the graph can go on and offline sometimes. and usually during very large payout sessions.
If your miner itself is still connected; then you are still generating shares even if the pool graph shows no hashrate.
Also note; your "Total pending value", and "balance" are two separate things.
"Total pending" can fluctuate based on price and demand on the exchanges.
"Balance" will not get smaller like the pending balance because it is all sold, and is actual final known credit for your shares.
All of these things are explained on the zpool.ca homepage, and at the bottom of your wallet page:
" * a general estimate from current exchange rates
** bitstamp 6 105.00 USD/BTC
*** Payouts 60+ days old are purged.
**** Total Unpaid is a combination of your confirmed Balance and your fluctuating total pending. This value will rarely be constant."