Myriad issues - How To Access Someone In Senior Management?

I honestly don't even know where to start.

We bought a small restaurant/catering company in 2024 that already used Comcast Business Internet. So we opened our own service and added voice. I thought I had set up voicemail last year, but it wasn't on our account.... so a few months ago, I reached out to find out what I needed to do to add that, and also mentioned that we were having intermittent internet outages. 

The sales rep created a bundle for me that included a business mobile phone, voicemail on my landline, and updated internet equipment which was apparently indicated by the system. A week later, the cell phone arrived, and when I tried to activate it, I had nothing but trouble. Turned out the sales rep had attached all the new contracted choices to the account of the *previous* business owners.

The number of hoops through which I've had to jump over the past two months is dizzying -- and I *still* don't have voicemail, an operational cell phone, or decent internet access. This has cost me multiple contracts and I lose phone calls daily. Calling customer support is infuriating because I will end up on the phone for what can turn out to be hours, going over everything and trying to resolve issues that clearly nobody else understands, either. I absolutely refuse to go back to the original sales rep who messed all of this up in the first place -- I already had to dal with her re-writing the contract multiple times and I don't trust her to be able to fix a stamp to an envelope, let alone fix all that's gone wrong here. 

How can I reach someone who has the authority to really help here? What I need done:
- Set up a site visit to do whatever they were supposed to do with my equipment -- which I absolutely should not have to pay for, since the sales rep told me they indicated it was outdated or something;

- Get my voicemail up and running, since I'm supposedly paying for it and there's no access to it on my portal

- Take back this useless mobile phone and refund our money because I won't get the time I lost back

- Provide us with an actual human to guide us through getting things operational so that our systems actually work from day to day. I can't have our POS and delivery tablets losing connection for no reason -- we pay for way more bandwidth than we need. 

Anything that can be done to help me would be amazing. I work every single day for 14-16 hours -- most of it on my feet -- and I do not have the ability to spend any more time on the phone trying to navigate this.