I tried everything with my oldest son with the toilet training the treats/rewards, sticker charts etc. What worked for me was what I called the surprise box.  I just got a bright colorful box from the reject/2 dollar shop, and I filled it up with special and different lollies, and chocolates.  Things like those bug chocolates you can get, and gold coin little soccer balls, etc etc.  I just made sure that they were things that we never usuallu had so they were more special.  Everytime he used the toilet correctly he got to pick one from the surprise box.

I think it took about a week, and we were done.  Just an idea, it worked fro me.

Wish you the best.