Charges I didn't agree to

Back in September, I was put in charge of our internet bill because my roommate was moving out. I went into an xfinity store with the roommate so we can transfer ownership of the new plan/get a new customer deal again since that's what he got back two years ago. Keep in mind that my roommate also inherited the responsibility from a previous roommate 4 years ago. Anyways, I went into xfinity store to just get the same exact plan that we've always had but this time with the new customer deal under my name. The employee that was helping me out at the time said he wanted to check our usage just to make sure we have the right plan and he said we always were just under the 1.2 TB every month so we had the Gigabit Extra. He also told us there was a price increase compared to the last time we had the plan and so what was $85 was now going to be $105. I just agreed since the plan we've had always worked for us. About 5 days before the end of the month, I get a text saying we've used 100% of our internet. I show my past roommate and he says he's never gotten that text before. I'm looking into it and I'm trying to figure out what's changed in terms of usage in the household and nothing drastic changed that would explain what ended up to be 200+ GB of extra usage at the end of the month. I wanted to give it another month to see if october was the same so I changed our password and also saw the same thing, high usage. I go back to xfinity store near the end of October to upgrade to the unlimited plan and I told the employee helping me out what the previous guy said back in September, "We were always below the 1.2 TB" and that I don't know how to explain the high usage. The current employee checks and says that the plan for the past 4 years (before it changed to me) was always on the unlimited plan xFi Complete. He also said that we have always used more than 1.2 TB every month. Afterwards, I am taking a deeper look into the statements that I've received as well as the last statement that my previous roommate received when he had the promotional discount and was just very confused. I originally went into Xfinity in September to ask for the exact same plan (which was Gigabit Extra + xFi Complete) but it turns out I just had Gigabit Extra + a NOW TV subscription for $20 that I knew nothing about and I didn't ask for it. Now it seems like the first employee lied about the price increase, gave me a subscription that I didn't ask for, and then I had to go through the process of adding xFi complete for even more money. I went through the process of cancelling NOW TV but I still don't see the change in my current bill. 

Things to note:
Looking at my former roommates statement, the monthly charge was always $116 and that was Gigabit Extra Internet. This included a 24 month $26.00 Service Discount and $5.00 Automatic Payments Discount. There was the add on of xFi Complete which seemed to be +$0 because there was a 24 month $25 Service Discount as well. This all included Peacock as well. Final monthly cost was $85

The plan I was on after going to the Xfinity store the first time and asking for the same plan but with the new customer discount was just the $116 for the Gigabit Extra Internet + a NOW TV $20 Subscription I didn't ask for. This also included a Promotional discount of $21.00 and a $10.00 Automatic Payments Discount. Final monthly cost was $105

My current plan after going to the Xfinity store and also cancelling NOW TV is the $116 for Gigabit Extra Internet. This also included a Promotional discount of $21.00 and a $10.00 Automatic Payments Discount. I also have the add on xFi Complete for $25.00. Final Monthly cost (projected for next month) is now $110

My main questions are:

1. How can I get compensated for a subscription that was forced on my account the past 3 months?

2. How can I remove this NOW TV charge on this current months bill that I have to pay in a couple days from now?

3. How can I bring the total monthly cost down to $85 which was the monthly price before? I see that I don't have that $25 service discount that my former roommate had.