I have used the surveys and have always received the gold from them, not sure why there is a problem with others not getting them. Have you completed the surveys honestly and not rush though them as there are specific question(s) in most that are there to root out those that aren't giving serious answers. Also at any point while taking the specific survey does it tell you that you don't qualify for it?
Surveys are from a third party. If you are sure you answered all of the questions, accurately and truthfully:
Click "Support" in the bottom left corner of the buy gold menu gyazo.com/a250f4a8ad9b45d4a47a2a162f10cc81 In your report be sure to include what survey provider you used, and which of their surveys you have completed. The Community Managers, whom handle payment, will work with the survey company to find out why Bytro was never paid for your survey.
As long as Bytro is paid for your survey, your gold is paid to you.
I see that @WiseOdin has answered your question, but again any issues please contact the payment dept (by creating a ticket) and they will assist you with this issue it can often take 24hrs or more to get gold you earn as it is a third party but the folks at Bytro HQ will assist once you make a ticket