Customer service

I had spoken with 2 agents today. I also received 2 surveys almost back to back so the survey I took, I’m assuming was for the 2 agent (which was amazing!) since it was the most recent. But I wanted my experience with the 1st agent notated. She was extremely rude. I had called in because my bill is supposed to be $70 and I have been getting charged $85+ for equipment fee that I do not have. I pulled up the July bill and stated I was billed $85, but charged $70 because of the credit for the previous month, so I technically never received a credit. She starts talking down to me and says what is 85-15? 70 correct? So you received a credit. I explained my bill is supposed to be $70, not $85, so yes I received a $15 credit, but I was also charged and extra $15 so that would equal $0 credit. (I was being charged an extra $15 for 4 months) She continued arguing with me, then when I asked to speak to a supervisor, she refused so I ended up hanging up and calling back to speak with someone else. The 2nd agent confirmed I was right, and should be getting more credit that the first agent was telling me.