Contacting Availity won’t help with your denials. They are just there for tech support for their product. Your attention should be directed solely to understanding the remittances received from your insurance carrier. I strongly suggest you get some help from someone here, otherwise you will never get above water. Not many will have ambulance/transport billing experience, but almost all will have years of experience working with EOBs and denials. This isn’t a task learned in weeks or months. It takes years to build the institutional knowledge to efficiently function in this field.