On the game episode I can't enter a referral code?

Ok so I entered my iPhones referral code to my iPod and vise versa but now it won't let me enter any more. I'm pretty sure it's because other people have to use mine first? Please enter mine I'll love you forever!
XA4FGJT5DB
7GC6GH6SJ0

Added (1). Also please add yours!

8WS6MGWTHP

3S06H6GCD2 is mine.

W55ZHLYSXZ please use mine

NYZ6FT05Q6 please enter mine!

CW0DX0Z8Q8 please use thanks

7ET458CGC0 please use mine!

NJT7DGTCH8 Please everyone use mine too!

5TARSDFVY use mine!

5TARSDFVY use mine!

5TARSDFVY use mine!

6LTX00U7SM USE MINE!

6LTX00U7SM USE MINE!

6LTX00U7SM USE MINE!

6LTX00U7SM USE MINE!

6LTX00U7SM USE MINE!

6LTX00U7SM USE MINE!

VZVLWDFMB0 is my code

Mine is RJ68NA6BYH