Keep getting declined charges for account that I don't remember

On my account, Musescore keeps trying to charge me $50 on a card that I closed a while ago. I can't remember the email I signed up with. I tried contacting them, but got no response. Their T&C reads "You agree to pay MuseScore all reasonable attorney's fees and costs incurred by MuseScore to collect any past due amounts". How can I fix this if support wont even respond?