Lied to about credit

On August 31st I called about my internet being much slower than what I was paying for. During the phone called they experienced many issues with resolving it and it ended up being an hour long ordeal. Well at the end of it I ended up upgrading my internet speed and was told that I would receive a credit for one month's bill. I was very surprised but extremely grateful. Well fast forward one month to September 28th and I realized I never received the credit. I called again and spoke with a gentleman who saw that there was a note about the credit but nothing any further. He said he had to reach out to the supervisor to get it approved during that time he offered to upgrade my internet again for  no additional charge which I said okay why not. After all of this he said that I should be receiving an email a 3-4 business days about my credit. Well a few weeks went buy and nothing at all... I decided to chat with an associate on Friday October 18th and when they were "looking into it" the chat suddenly stopped and another associate came on. I became frustrated so I said I would like a call back. They said that I would receive one at 12pm... The call never came. Extremely upset the next day I called and spoke with a woman who said that the credit request ticket was not done correctly and she would do it again for me. She assured me that I would receive an email on Monday the 21st and everything will be resolved and I would not have to call back again... It is now Tuesday the 22nd and I did not receive anything.. I called again and spoke to a man who said he could not find any tickets in my account but will contact the credit dept so it can be resolved and informed me that any time a ticket it opened I should receive a text (I never did until today)... He also said they will need to listen to the phone calls so I have him the date from the first call which was August 31st and there were multiple after that saying that I would be getting the credit for a full months bill. After waiting on hold he came back to tell me that I would not be receiving a credit but they told him it was up to his discretion of how much to give me and he thinks I deserved $15-20 for the internet issue. I demanded to speak to a manager and he said I would receive a call back within an hour.. That was at 5pm and it is now 7pm and no call was made. I am extremely upset that I was lied to on multiple occasions and feel like I was told what they thought I wanted to hear to get me off the phone. I hate to say it but I am looking for ways to now get out of my contract with Xfinity after being a customer for many years but customer service is a big deal to me and they honestly are terrible.