recurrent charge after one-time donation

It happened on 2 of our credit cards. After we donate $55 dollars in March 2016, ActBlue started to charge our credit cards monthly. Even after we dispute one time, they returned part of the credit but charged us again on the same day. Only when we were collecting our statements for the 2016 tax submission last week that we realized they kept charging us after our dispute. We contacted them and asked for refund. Their reply was "Unfortunately, we’re only able to refund inadvertent contributions that have occurred within the past 90 days. " What a scam organization!