@germain18_2006 I don't know exactly what proof of pre order is, maybe the email with shipping details. Proof of purchase I assume we will receive papers from Rogers as usual when you pickup the phone since you don't pay for the phone in store it goes on your bill.
When doing the upgrade or new activation, they give u a small receipt at the end of the transaction. It is shows that IMEI number of the device, which device and whatnot. That is what they are looking for 🙂