iPhone 14 - dual Xfinity Mobile lined

Hi,

Before I ported over a new number and bought an iPhone 14 Pro, I was promised that I would be able to run two active lines on one phone. Now I'm being told that's not possible, both at the store level (where I kind of expected it) and at the Tier 2/Advanced Support level. 

Has anyone had a different experience? Is anyone able to run two active lines on the iPhone 14 (as opposed to turning off one line to use the other, which is the best Xfinity could offer)? 

Thanks.