It looks as if you will need to enroll in the Direct Debit method.
Wire Transfers are useful, but would not normally be used for routine bill payments. (Read about the difference between ACH billpay systems and Wire Transfers
HERE.)
Thanks
mia, I again spoke to a Citi agent, the only option to avoid the $25 is the DD payment. According to the agent, Amex has disabled electronic funds transfer recently, which made my payment option switch to "paper check" automatically. What Citi does is to try to send money using any other available options once requested, so they just sent my payment by a cheque instead of the usual electronic transfer...
Setting up the DD takes a few weeks, I have to use the wire transfer...not happy.