When you request an SMS 2FA code, they're blindly sending an auth code to your phone number over SMS, that's all they know. That number could be registered to a

When you request an SMS 2FA code, they're blindly sending an auth code to your phone number over SMS, that's all they know. That number could be registered to any SIM card which could be in any device. Someone could have socially engineered a rep at your carrier to have that number transferred to their device, which is a real thing that happens.