Hi there,
can you let me know what tool you use, is the proxy ip dedicated or is public.
I can fix it for you, i manage around 600 social media accounts thru a tool i have, and i never have verification on facebook neither any block.
So i can adjust it also for your facebook and you never have any issue with ip or similar.
please chat with me for more details so we can arrange all of these issues and you feel relaxed.
best regards,