I was yelled and scolded by AT&T customer representative.

I can't explain how disappointed I am with AT&T's customer service.
I've been with AT&T for 14 years and It was a pretty pleasant experience until today.

It was horrific, I felt like all the representatives teamed up against me while talking on the phone.
I know they share notes on my account and know what happened on each call. I have never felt so offended like today on the phone, especially with customer service.

Long story short,

I had 3 unused tablet lines that I'm paying about $37. I finally got to removed those 3 lines today. I couldn't remove them before due to contract issue. (My parents got the tablets thinking they are "FREE", offered by a sales rep at a AT&T retail store) I asked the representative if there's any discount they can give for my current bill because of what I had to go through with AT&T services and she told me she can give a courtesy discount of 25 dollars. I asked if I could speak to someone superior and she said she will let her supervisor call me. 

So I waited, and Kelby the Escalation department supervisor, (she refused to give out her last name initial due to her security issue), said she can't do anything because there is no error in the service and because I "REFUSED" to get a courtesy discount of 25 dollars by asking to speak to a superior instead of just getting the courtesy discount and hang up the phone. 

Kelby said I should've just taken the courtesy discount when the other associate offered.
I don't understand her attitude, I told her I didn't decline to get the courtesy offer, I just asked to speak to a superior to see if anything else can be done but unfortunately, Kelby was not in the mood to help. She kept cutting me off while I'm trying to explain what happened and when I try to repeat what she said to make it clear we are on the same page.

I asked Kelby who can I speak to since she can't help me, she said "no one."

She said she the highest person that I can speak to and she can't help me.

I felt helpless and I was filled with frustration during this phone call.

When I called again to speak to someone else to see if I can get the courtesy discount, Eric, the rep who handle my call spoke very fast with scolding tone. He seemed like he already knew what happened. I assume he works in the same place with Kelby. Or he got a special note from Kelby.

I've worked in customer service before. I was on of them. However, what they did to me, the way they treated me should not be repeated to other customers.

I really wish AT&T trained their associates to treat their customers with respect.

Who am I supposed to get adequate help when the "escalation supervisor" treats her customer with no respect?