If you don't have a lot of TWO-WAY regular engagement with people on social networks don't expect them to even notice your survey, let alone fill it out. Expect about a 0.5% response rate at best.
If you need more survey answers than you getting, you either need to: 1) increase reach to cover your low response rate, or 2) generate more interest per exposure to increase response or 3) both.
You can increase reach by buying more exposures with Facebook Ads, Google Ads, LinkedIn Ads... You can also do directly email by buying mailing lists or responses from SurveyMonkey, ConstantComment, etc. Or buy survey respondents using Amazon Mechanical Turk. This is usually the "easiest" and "fastest" way to increase your total responses, as long as you have money to throw at the problem, because typically you use pay per response approaches, so the social networks can flood their networks till you've got the responses you paid for.
The alternative is to generate more interest for each exposure. Filling out a survey is an unrewarding time consuming activity. You need to find some other way to make it rewarding enough for someone to take that time instead of do something else. Many surveyors offer a gift card or some cash compensation, or if the surveyor offers a product or service some kind of discount or freebie.
An alternative to paying everyone who responds is to run a contest and offer a single prize or small number of prizes to a few respondents selected randomly. As you might guess, you'll have more respondents if the chances of winning appear to be high, and fewer respondents if the changes of winning are low, or the prize isn't that valuable.
Keep in mind that monetary and prize incentives and ad selection bias can skew your results. Results tend to be most accurate when having accurate results is also most valuable to the survey participant.