How do you get someone to follow through on an issue with incorrect billing after contract renewal?

My business has been with Comcast for over 13 years. Every couple years when our discounts expire, I call in to get into a new promotion to keep the bills cost down. I did this in March 2026, business as usual. In order to get into a promotion that would get a rate I was satisfied with, we were offered a "free" mobile phone line, I was told exactly what my new bill amount would be, asked to make a small one-time payment to cover taxes on the mobile phone (which I was told would be credited back on my next statement), and on I went. My regular phone + internet bill is now coming in significantly higher than the contract I signed, and I am receiving a separate bill being auto-charged to my credit card- COMPLETELY UNAUTHORIZED- for the mobile phone account. I reached out directly to my sales rep several times via phone and email, to be completely ignored. I have called my "dedicated business account executive" who told me sorry, not sorry, I can't help you have to call the 1-800 number, which I then have done several times (you can check call records). Finally on Monday of this week I spoke to someone in the Customer Loyalty department- Sylvia- who heard me, understood my concerns, gave me some semblance of hope that the issue would be resolved- that she would reach out to the Sales Rep & their Supervisor who would get in contact with me in no less than 1 business day. I also asked Sylvia for her contact info in the event that I never heard from the supervisor, she said she did not have a direct line but would send me an email with her contact info. Call ends. I received no email from this agent in the customer loyalty department, no call or contact from the supervisor of the sales rep, absolutely zero attempt at resolution. I am trying to run a business here and do not have countless hours to spend on the phone chasing my tail and telling my story from scratch to rectify what feels like complete FRAUD. Plain and simple, I have a contract in hand that I signed for a specific monthly billing amount. Nowhere does there exist any type of authorization for an auto charge to my credit card for an account I did not sign up for. I have tried to handle this civilly, but this type of bait & switch behavior is unacceptable. If I do not receive contact and resolution by the end of this week I will gladly find another company that will buy out our contract and give us a rate that I approve. Not some cloak and dagger nonsense where I cant even get my issue heard. 

I would also like to mention that the Customer Loyalty agent told me "this is far from the first time this has happened". Unacceptable.