After receiving the call I did my research and found out the call is a widespread scam and the fraudsters are constantly changing tactics. Pre-Covid they were calling from the UK via spoofed numbers, they are now active again but from call centers abroad. They claim to be calling from Carphone Warehouse, Fone City, Phone World, Smartphone Ltd, and other real and fake company names.
They offer very cheap deals even claiming they'll pay off your old contract so you can keep your number. Then use the details you give them to order multiple phone contracts in your name for different, high-end phones. They track the orders by using their own email addresses and then call once delivered to claim they made a mistake and you have someone else's order.
They give addresses to send back the phones via your local Post Office, then wait at these addresses for your package(s) to arrive and steal the phones. This leaves victims with multiple, expensive 24-month contracts in their name as well as damaged credit scores.
If you've been a victim or have information about this scam, please share your experience or information by leaving a comment below.