File a complaint - We lost our mobile number after 20 years!!!!

Where do I start? Description of the problem: Customer calls to deactivate a line no longer needed. Xfinity agent deactivates that line, PLUS our other MAIN line - October 4th. Here is where the journey starts. Agent tries to "fix the glitch" by ordering a new SIM card. Also tells me I can go into the store to get this resolved (all the while the number is still working, but the online account shows deactivated). Person in store can't resolve because the account is so messed up, tells me it should be cleared up in 2 days. Nope. Number still working. I receive the new SIM card. In the meantime, I have ordered a new iPhone 14 Pro Max for myself and receive it. Great, I'll activate this, move my wife's line that was accidentally deactivated to my old iPhone 12 Pro. I have been working ever since I received my 14 to have the iPhone 12 activated for my wife, we're talking weeks, all the while her number is still working. Today I chat with the team after MONDAY they said they were activating the line and am informed that since it has been more than 30 days, the line is no longer active and cannot be restored. We are losing a business number that we have had for over 20 years because someone at Xfinity messed up. Supervisor closes chat with, sorry you did this, good luck. This is not acceptable. What is Xfinity going to do to fix this.