Take pictures. When you call the authorities, take the name of the person you spoke to and find out what their title is. Keep notes, record the dates. After a month or so if nothing happens, contact your local news station and report what's going on. Have good, clear photos, taken with your phone held sideways, and short videos taken close up. Good luck.
This is great advice.
Animal abuse/neglect is a crime, and animals cannot advocate for themselves to stop the suffering.