Upgrade ordered by phone was set up as a port-in with someone else's number, so my new iPhone 18 Pro Max can't activate

I'm an existing Xfinity Mobile customer. I called Xfinity to upgrade my current line to an iPhone 18 Pro Max. Instead, the agent set it up as a new line transferring a number from another carrier, and typed in a number that apparently belongs to Verizon or AT&T. It isn't my number, so the transfer can never go through and the iPhone won't activate.

What I've tried so far:

Called customer service several times and went to a store. Nobody could fix it.

Asked to return the phone. I was told a technical problem was delaying the return label and it would arrive in two days. I never got a label, an email or a case number. I have 14 days to return it but haven't received any label .

Number Lock is also on for my line.

Went to a a physical store and they said they couldn't help me if as i didn't buy from a physical store 

My questions:

Has anyone had a wrong number put on their order? How did you get it cancelled?

Is there a specific team or phrase that gets this fixed, like the porting or activations team, or a device swap?

Xfinity has been incredibly unhelpful and I've been constantly shunted between physical and online stores/calls.I don't know what to do. Would appreciate any help