Still have not recieved trade-in credit and no longer can look at status of my trade-in.

I switched to Xfinity mobile about 3 months ago, because of a promotion they were having at the time.  The promotion was supposed to be the device (Iphone 16 Pro) was on Xfinity as long as I did a trade-in and created a new account with a new line.  Yes I was supposed to only receive $25/mth credit for my Iphone 12 Pro trade-in, but the representative I spoke to one the phone informed me that the remainder amount would be covered by Xfinity via credits per month which amounted to $16.66/mth so I would have no payments for my device. I shipped my trade-in with the box I was sent to Assurant.  I have attached a picture of the promotion that I signed up for and the USPS tracking information showing it was delivered 2 months ago.  I have tried to go and look at status of my trade-in to see what's going on, I have chatted with support SEVERAL times, and keep getting told it's being processed or it can take up to 3 months to see the credit and I'm on my 3rd bill and still nothing.  Customer service just told me today that they have no record of any other credits except the $25/mth trade in credit!! I'm so upset with all this I'm ready to switch to another company and pull ALL my services away from them.  I thought this would be better and cheaper than I was paying but they aren't even holding true to their word.  I just want my bill credits as discussed, and the money back for the past couple months that I've had to pay for my device.  I was told I would have to only pay the first month and taxes up front when ordering service and all the credits will be applied as soon as they received my phone.  I have the Unlimited Plus plan and I have attached a screenshot of that as well.  I should not be having to pay anything for my device. I as well as WAYYYY to many others are having to deal with this and that is not a very good business plan for you all. If I have to I will go on several platforms and post how awful your service is and how you lie to your customers.  I have proof of my promotions I should be getting as well as proof that my trade-in was delivered.