Can't seem to be able to get the phone I paid for

I'll try to be brief here because it's been a 3 week process.

I ordered a new phone on July 26th under the existing customer promo. The phone was mailed to me via Fedex, slated to arrive on July 28th. Long story short, Fedex lost the package and don't know where it is.

I would have thought I could just have a new one sent out as a third party lost it, but now, 2 weeks on, Xfinity doesn't want to send me the phone I paid for. Instead, they added another line, charged me full rate for the phone and sent it out. Of course, that one made it to my doorstep, but that needed to be cancelled and sent back because that line shouldn't have been created. So now I have to go to a Fedex store to send it back. All the while, they have an "open ticket" on my original phone that got lost, and don't want to send me a new one at all for that line.

They say now it'll be "resolved by August 20th", which I have no faith in, but that it is to essentially cancel that phone. So now what will happen I'm sure when they go to order a new one for me, is they'll say "oh I'm sorry, that promotion has ended and the phone is now full price".

When your Amazon package gets lost, they immediately send you a new one. Xfinity charges you for a new phone that you have to take time to physically return, and now you're out the cost of two phones until they can finish whatever crazy process they have. 

Customer service reps have done their best throughout this process, my frustration is with the system and process. But my question is, how do I get my new phone?