If leads are not coming into your account but are showing up on Facebook then you are missing StreetText in the lead ad integration step which can be found here: https://business.facebook.com/settings/leads-accesses
If this link doesn't take you to the Lead Access section on Facebook, go to Business Settings and find 'Lead Access' under Integrations.
Please follow the steps in this picture to make sure StreetText is connected as a CRM in your lead access: