If you've ordered RFID charging card and keytag they will be sent to you via Posti directly to the given address in your customer account. Printing and deliveries are handled on a weekly basis so in all cases the RFIDs should arrive within 2 weeks from the order.
While waiting for the RFIDs to arrive, you can always use the mobile app to start charging. The credentials are sent to you right after the registration. Once the RFIDs arrive, they are ready-linked to your customer account and ready for use right away.
You can find the receipt of the payment in your Account History by logging in to your customer portal.