Trouble Reactivating Cancelled Small Business Landline Phone

AT&T cancelled our phone line in May 2023.  It has stayed inactive since then because no one will help.  I've made several appointments for someone to come out and reactivate the phone line in person, but no one ever shows up. I was given emails to a couple different managers, but they have not once replied to any of my messages.  I'm at a loss here of what to do anymore. Can anybody help?