First go here and input your ether address where you are holding PoSToken : https://calculator.postoken.org
If it shows reward then follow these steps.
Send 0 PoS to your own address (where you are holding PoS) with gas price 21 gwei and for gas limit either go with suggested by MEW or put 200k. Do transaction, once confirmed go back to PoS calculator and check if it doesn't show any reward means you are good. You can repeat process every 3 days.
Thanks.
You are welcome. One more thing, for gas price check here: https://ethgasstation.info
5 gwei is enough now.