Sorry to hear that Cobra but what i suggest you do,is to copy the e-mail you recieved from go fish and on the offers page click on support,which will show you all the offers you have either viewed or completed and check that the big fish offer is completed.If it says viewed and the date click on contact and they will ask you for a couple of related details and in the big empty box paste the recieved e-mail from big fish in there and submit it to trialpay and they will sort you out.As it's trialpay who credit your WGT account hence why WGT accepts no responsibility being only a 3rd party.
HOPE THIS HELPS
RUSSELL
P.S hope you have cancelled the 7 day free trial to the go fish club or you wil get charged