I did keep it as I already had to go through the trouble of setting up a direct deposit and all that so I kept and used the direct deposit as my monthly RP allowance, and I would also get a little bonus RP with those purchases as well. That being said that's not the point of this thread
fine. then lets get to the point.
The card is held by Amex/Serve who have a contract with League about the rewards earned being converted to RP and directly transferred into your associated LoL account.
Riot is not the bank/creditor.
You dont have a contract with riot when it comes to the card, you have a contract with Amex/Serve.
Therefore, any changes or terminations -by law- have to be communicated to the cardholder by the financial institution who issued the card.
Contracts concerning your card:
You > Creditor/Bank: yes
Riot > Creditor Bank: yes
You >Riot: no