I had the same problem and did the same thing as you when my son was 21months old. I took one week vacation and didn't go out and trained him for whole day and due to my bad temper I also blamed him. Then after the whole week of course not successful. I gave up. After around 3 months time, one day he took the potty from toilet and told me "Mom, I want to wee wee."
I will suggest may be now he's not ready. Don't force him.