Instead of posting a link to a survey in a Facebook group with potential customers, post that you're doing a research project and would love to interview some people that do [whatever your target market does].
Here's my theory: People don't like filling out surveys because it feels cold, and impersonal. On the other hand, answering questions being asked by a human interviewer, even if they are the same questions, makes them feel important because of the personal touch. Someone else is taking time from their day to ask the questions, so it's more reciprocal.
This is an example of the classic "do things that don't scale" advice.
Here was the message I posted in a large Facebook group:
Yo! If you listen to riddim mixes (or really any kind), I would love to interview you for a research project I'm doing on EDM & DJ culture. Would just be a few questions via messenger about your listening habits and what matters to you as a listener.
Please like or comment if you want to participate and watch out for a dm from me! Peace✌️
It's been about 8 hours, and I have 12 people that volunteered to be interviewed. I conducted 5 interviews in the first few hours. I highly doubt I'd have had that engagement rate with a survey link.