When you file a bankruptcy then that immediately puts a stop to their taking money from your bank account or garnishing your wages. If you are working though the judge will change your Chapter 7 to a Chapter 13 and you'd have to make a five year repayment plan and pay toward that judgment. Your attorney will help you make that plan. Tell that collection agency you're in the process of doing a bankruptcy. They will continue to monitor your accounts and check to be sure that you do file a bankruptcy and then they will file a claim against your bankruptcy so be sure to list them and the company you owe on your bankruptcy. That collection agency can also put a lien against anything you own, and in some cases they can put a lien against your parents assets if you live with them. So it's best to make some kind of repayment plan with them according to your income, but is also good to have a bankruptcy solve the matter.
Yes, they can snatch money from your bank account if they have a judgment.
Did you show up for court? If you didn't, you should have and argued that 8k figure. When people don't show up for court or "default", the judge gives the creditor whatever they are asking for!
If you are filing for bankruptcy, that means you *should* have a lawyer. Contact them and ask them what you should do.
I personally would carry cash for the time being though.