I have never had an ON card, but many others and hardly ever have cards with me when I call. They can always pull my info up by my social, phone, address, etc. You may ask for a supervisor and advise him/her of your situation. They should be able to help.
Personally I think it will be a little more complicated than simply asking them to cancel. My experience during divorce was that you can't simply call up a creditor and ask to be removed because you have a decree, especially if credit (loan, card, etc) was granted on BOTH of your incomes/credit scores. Instead, they will tell you the other party has to QUALIFY for said credit on their OWN before they will remove you. Then they have to involve the ex.
This becomes a royal pain if you are talking large amounts like car loans, etc. However, depending on the ON card balance, it may be easier to just pay it off and then cancel the card since you don't speak with your ex. Doing so will surely irritate you by paying his bills, but it also eliminates risk from HIM ruining YOUR credit should he miss a payment or two or more. And that is worth quite a bit.
