You need to analyze your 'funnel' and find out where people are dropping off. What sort of traffic are you getting on your posts? What percentage actually click

You need to analyze your 'funnel' and find out where people are dropping off. What sort of traffic are you getting on your posts? What percentage actually click through to your site? What percentage of those visitors click 'buy' but don't actually buy anything? etc... Maybe you have a problem getting traffic. Maybe you have a problem with your product. Maybe both.