Super hard to grow! Facebook blocked me LOL

So I have been trying to get users on to a platform that I developed. I found some facebook groups which have large collections of the users that I think would benefit from my platform. I think these people would want to join. I started to send some messages to some people in one facebook group and got some interest and feedback but then I got blocked from facebook :$ (Zuckerberg strikes again!! lol). They froze my messaging ability for 3 days. I didn't even message that many people. I messaged 12 people, out of 12 I got 3 genuinely interested and they messaged back( although they haven't signed up yet?). This is pretty annoying cause its relevant to the people i'm messaging . It seems like it's pay to play with any of the social media companies. The only way to get users from social media is to directly advertise to them or to create your own facebook group then grow that into something substantial and then you can let your group know about your service/product. It seems like such a round about way of getting to customers.

This is where i'm at a complete loss for how startups grow really quickly. How are they growing so fast? SEO takes a million years to get any benefit from and using social media is a pay to play type of scene?! Unless you go viral but not all services are memeable and go viral.

Not sure what to do? My only thoughts now are that I need to start my own facebook group and grow that. Then in 2 years I can start to tell those people about my platform /s

Anyone got any ideas/suggestions? Should I just quit? All the cool kids are quiting LOL jk jk.