Frustrating trying to cancel service

I've used Comcast Business Internet service for more than 10 years, originally signed up through the company I worked for. I need to cancel the service today since I've just opened a new Xfinity Internet account and activated the service. I followed the instruction on https://business.comcast.com/support/article/account-management/cancel-or-make-changes-to-your-comcast-business-service to cancel by calling (800) 391-3000. The representative told me to send an email to nast_macdrequests@cable.comcast.com to cancel. And she said the request may take up to 10 days to process and the cancellation may take up to 30 days to complete. I couldn't talk to a manager when requested. It seems there is no other way to cancel. I am extremely frustrated that such a request can't be done on the phone and can take such a long time to complete. This is not how I imagine a business service would be like. I am wondering if this is what other people experienced with Comcast Business. Is there any better way to do this?