Trying to upgrade phone

I am trying to upgrade one of my Xfinity Mobile phones to a Samsung S25 Ultra (256GB, Titanium Black). I go through all the steps, including my trade-in of a Samsung S20 plus 5G (128GB ). I press "Add to Cart" and get a message saying something about "continuing with the replacement" or "removing the replacement?" Which ever I click on, it sends me to the message, "there is nothing in your cart. Continue shopping". I’ve used different devices, browsers, incognito, the Xfinity app and no luck. It’s been going on for at least 24 hours now. Should I buy it somewhere else or will this be fixed?