1) Someone whose source of income is based on the haram money gave me some money when I visited their place as a form of gift. Can I use that money, is it haram?

2) What about eating when I went to their place? And some other which they give me.

1) If you know it’s haram for sure pay it in charity

2) Try and avoid it if your it’s from a haram source otherwise you assume it’s halal