Normally, the bank has your employer data (they see the incoming salaries).
They will try to work with you on a plan how to get out of the hole, but as a last resort, they lock your account until the salaries / unemployment pay have paid the open bill, or - if that won't work, or you move your income to another bank - they contact your employer / the government to garnish your salary / unemployment income.
Long-term, the Schufa entry is the bigger issue, as you will be unable to get any loans - for furniture, car, a house, or whatever; nobody wants to lend money to someone who is marked as 'doesn't pay back'.
Contact then proactively, explain the situation, and ask for help to get it back to normal. You are not the only one in trouble, and they will be willing to help you.