Hi there, @Theresa247! SIM cards may not be shared between two devices. Each SIM card is assigned to a device and paired together. You may not simply pop a SIM card out of one device and use it immediately in another device. You will need to wait for the new SIM card.
Hi, therhotonjoey. Please visit a Boost Mobile store to purchase the SIM card. Please visit https://www.boostmobile.com/#!/store/ to find the nearest Boost Mobile store.
They should be able to assist you. What happens when you enter the IMEI on the BYOD tool https://activate.boostmobile.com/bring-your-phone?intnav=TopNav:Phones:BringYourPhone?
If it is a brand new Boost Mobile phone, it should've come with the SIM card installed. What happened with the SIM card that you got with the device?