We have no way of investigating that for you. You'll need to check the court file.
The summons is for what purpose? Is it a summons and complaint for default on the credit card? A summons for a hearing on enforcing the judgment they somehow obtained? A summons for some other purpose?
Money in a joint account is presumed to be jointly owned. You may argue to the court that the only money in the account is money you have deposited, and to try to get the court to release the funds on that basis.Quoting dmbfanindy

