I used to sell AT&T cell phones when I worked for FranklinCovey. Even though it was the one thing I got a commission for, I used to talk people out of buying a plan with AT&T. Many people bought one anyway because AT&T had the coolest phones.
The reason I try to get out of it was because I hated calling their service line to set up the account. You would not believe how hard it was to get them to take the money from a new subscriber. Often times I would be told to hang up and dial another number because of the plan the customer chose. This was after a long time on hold and navigating multiple voice mail options.
I would think there would be a fast track to the "we'll take your money now" line, but alas there was not. The thing is when a customer calls your company they don't understand your internal departments or divisions. They called to talk to or buy from your company, not to deal with your organizational silos. Customers don't understand why they would need to dial another number for your same company, and they shouldn't have to.
Does everyone who works for you understand they work for the same company? What would happen if you called the wrong department in your company? Would you be helped, or told to dial a different number?