I'll assume you mean credits, not coins.
If you've spent money, include in your contact that you intend to cancel the transaction unless something is done. Give them a deadline.
Yes. Many are scams. WGT disavows all responsibility, so don't even try that route.
The most reliable method currently is videos, and even there it's only reliable on mobile. If you don't have a mobile device, there are two quite good emulators for PC/Mac, Nox and BlueStacks.
Surveys are a bit spotty, but if you stick with those offered by Peanut Labs, you'll get a few credits along.
Good Luck. I have all the best equipment and gift more to folk, all from just videos and surveys. You needn't ever spend a dime here.