When you received the notice of the bank account levy from the bank, you have/had 10 days to file with the court a "claim of exemption" for amounts held in your bank account.
Here is a link to claiming exemptions:
https://www.courts.ca.gov/1327.htm#acc13841
I am assuming that you at one time paid on the debt using a check, which provided the judgment creditor with the bank account information necessary for the levy.
You should have been receiving since 2012 correspondence from the creditor that informed you of your default on the credit account for nonpayment, and you should have received a summons and complaint notifying you of the lawsuit filed against you for nonpayment, and you should have received notice from your bank of the levy, used to satisfy the judgment.
If you did not receive any notices at all, or you dispute the legitimacy of the debt, you can consult with an attorney in your area for a personal review. If you agree you owe money to the creditor, however, collection efforts will continue until the debt is paid in full.
Good luck.