You have the obligation to support your parents. You just can't let your parents have nowhere to live, and you can't let them go hungry. You just have to make sure that their life is necessary.

But as you said, you have no obligation. Help me pay it back if you can. If not, it can be ignored. According to the custom, you have a brother, and these words should mainly be borne by your brother. Don't worry about gossip, your actual situation is there, people are reasonable, and they won't say anything about you just because of a few words from their stepmother.