It's too bad you didn't see this year-old thread before you attempted any. There are many people on this site who are more than willing to help you with tips on looking for the right surveys to attempt, how to do them and which ones to avoid.
Those phishing expeditions are easily avoided. For six years I supported my WGT habit and gifted plenty, acquiring upwards of 3,000 credits a month on surveys and videos. More than 2/3 of those credits were from surveys. Not a dime of my own money (not even a credit card on file).
Never give any information traceable back to you. No phone number, no email, no name. If they ask, drop out and try a different one. On average I was able to complete a survey every day or two and attempted countless others that either paid nothing or 5 credits. I've never received spam or phone calls as a result. It takes a lot of time and patience to be that careful but it does pay off.
It helps to remember that a survey isn't limited to WGT customers. The same survey is placed by the survey taker on many websites. You are competing with millions of people on many other game sites to get one of a thousand or two slots. The odds are very stacked against you getting to complete one.
Some of the survey wholesalers track a few key demographic answers for their clients. Those particular ones will disqualify you if you attempt to be a white male in one but a Hispanic female in another. I always just answered truthfully and let the chips fall where they may.
I don't attempt surveys any more as there are a few who put up surveys, collecting the information while having no intention of honoring the credit payout. WGT has made it crystal clear that they have no problem supplying access through their website to those and will do absolutely nothing to help or protect their customers. Apparently they endorse allowing those companies to commit fraud on WGT customers.