Has Gcash replied to you already?
I got the 4-digit code from the text notification. Maybe you should check it if you still have it.
This is what mine said(I altered it a little):
"1/3 You have paid P100.00 GCash to PP*4042CODE on 03-03-16 07:18 AM. Your new balance is *****. Ref. No. ***********. For your protection, please immediately..."
4042(altered) was my code.
Don't expect to get the P100.00 back though. It's for authorization purposes and should supposedly be refunded w/in a few days but it probably won't be. Lol. In fact, based on the complaints in this community, try not to use Gcash for any refund transactions.