I did enter stocks.exchange address and paymentID then clicked SEND and just waited... that's it, after few hours I've came back to wallet and that's what I got :S
Open a ticket on stocks.exchange and explain what happened.
I had the same problem last week (I put the payment id in the label box
). The team at stocks were very helpful, I opened a ticket on Saturday evening and on Monday morining they had found my coins and moved them to my wallet.