Hi, I had the same problem with my daughter and son, especially when it came time to clean their rooms.
I kept asking them the same thing over and over but they kept saying I can't.

So I used reverse phycology, and when they asked me for things when I went shopping I kept saying "I can't and "I don't want to" and eventually I think I got my point across because my children realised that they were missing out on more than what I was.

I hope this has helped, it worked wonders for me.