Just to know more about your marketing strategy, can you share your website URL and facebook page URL.
Are you doing only Facebook Ads? If so then I would suggest complete Digital Marketing strategy to get best ROI.
Digital Marketing Strategy Includes;
I am Digital Marketing Consultant with 10+ years of experience and I am shopify partner as well.
I hope these information will help you to understand Digital Marketing process.
If you are still unsure then please let me know. I'll be more than happy to help you to figureout your Facebook Ad strategy.
My Email: firstname.lastname@example.org