Billing problems not getting resolved

I traded in two devices. Apple iPhone 12 Pro ($600 trade-in credit that I am supposed to be receiving for it that which I am not). Apple 12 Pro Max which has an $830 trade-in credit applied to my account. Secondly, I had a promotional deal that should have been applied when I traded the two devices which is not being applied to my billing cycle as well. The promotion was buy one mobile line, get one mobile line free for 12 months. I've spoken to several people and nobody knows how to fix it. I am exhausted and about to report Xfinity to The Better Business Beauro due to this issue not being resolved properly. I was told the trade-in for the Apple 12 Pro was not processed because the item was not graded yet but both devices were shipped to Xfinity in great condition IN THE SAME PACKAGE. So how could one device be graded and the trade-in approved and the other not get graded if they were shipped together? Nobody seems to have answers for any of this. My Xfinity Mobile Services should only be costing me $96.92/mo right now because of all these deals and since everything is messed up for my billing it is now costing me $112.43/mo and NOBODY on the support teams knows how to fix the issue every single time I call.  I understand people at customer service are trying their best but the issue is not resolved and everyone I speak to just makes the situation more complicated. Also, they said somehow my internet services with Xfinity received a discount and I couldn't have the buy one line get one line deal because of that. The only problem is I never applied the discount to my internet services in the first place so I have no idea what has happened because I did not authorize any of this.