I was on the phone with a specialist for over an hour with a promised discount for an upgrade. After the hour plus, I was informed that the specialist misspoke and couldn't honor the discount. I am livid. Will be checking into other carriers.
All current discounts are listed online. Switching carriers isn't going to change that, your post is also missing details.
We don't know the tone of the conversation or how that back and forth went. If it was "I've been a long time customer what can you do for me?" then that places unrealistic pressure and results in a long non productive call.