Incorrect service price

On Sunday 2/10/2024 I was having some very bad connectivity. I chatted with an xfinity agent and they notified me that I have a modem (provided by xfinity) that can handle 200mbps. I have been paying for a 1000mbps service since May 2022. Monday 2/11/2024 I requested a refund for the difference of service for a second time since I got a $95 credit from the chat on the previous night. This refund is over $1000 for the course of 21 months that I have been paying for a service that I can not use the full capability’s of. I am more than happy to pay the price of the 200mbps service I’ve been able to use and I would like the difference back. I have talked to 10+ agent who all tell me different things about the refund amount is locked and they can’t tell me the exact amount I will receive. Some tell me it’s closed and they will make a new ticket. One credited my account $35 dollars. I am not on the phone with an agent who is telling me they are making another ticked because the other one was closed. I am formally writing to document the issues I have been so you can remediate this issue within 24-48 hours like the agents have said.