Horrible employees, terrible customer service response

I recently signed up for Xfinity mobile after hearing if I sign up for a new internet promotion, I would get 20 dollars off a month on my home internet bill. I called a sales member to do this. They signed me up for mobile first and then informed it would be same cost if I just kept my internet plan because I will get the discount. Well this sales rep was wrong, and basically the billing cycle came on my home internet and there was no discount. So I call back and was told that the reason I didn’t get a discount is because I didn’t get signed up into the new internet package and I would need to do that to have the discount. So he sends me a contact for new home internet that he said will reflect the discount. I get my next bill and of course the discount is not there. I call again multiple times and finally get someone who talks with a supervisor. They said the sales rep did the order wrong, and they needed to get me into home internet contract first before signing up for mobile. Then the second rep who signed me up for a new plan needed to inform me that my Xfinity line wouldn’t count for the discount because it was signed up before the new plan and the only way to get the discount is to get a second line. In short the supervisor said, the first  sales rep made a mistake that will cost you 240 a year, and the second rep tricked you into signing a year long contract with a fake promise of the mobile discount being applied, and that my previous plan was too old so I can’t go back to it. How a company can just have everyone do everything wrong and just tell me I have to pay for the mistake is beyond me. Awful customer service and awful company