There is a difference between a secured creditor and an unsecured creditor. A secured creditor is a creditor that you owe money to who can take property away from you if you fail to pay them what they are owed. Examples are car loans, mortgage loans, and some furniture loans.
An example of an unsecured creditor is a credit card debt. Medical bills are also unsecured, as is the IRS unless they have a lien filed against your property. The difference is, the IRS is a priority unsecured creditor and the debt to them is non-dischargeable in either a Chapter 7 or Chapter 13 bankruptcy unless the debt is old.
If you fall behind on your vehicle then they typically will call you after the first 30 days. They typically hound you after 60 days. Most of the time they start hunting for the car after 90 days.
Filing a Chapter 13 bankruptcy will stop the repossession and buy you 5 years to pay off the car. That almost always reduces the monthly payment on the vehicle.