We got a new corn hatchling on 7/17. I have tried to feed it twice, but it has refused. Here are all the details I have about its eating history.

Hatched 7/1
Ate for the 3rd time on 7/15 (I don't know the exact dates of the first 2 feedings)
Refused on 7/21
Refused on 7/26

I believe all 3 meals at the breeder were live, but the breeder said he would expect it to switch to f/t right away without trouble. The first time I tried live, then the 2nd time I tried frozen because I picked some up at the show that day.

When I tried to feed it, I put it in a small deli cup with nothing but the pinkie, put the cup in the snake's enclosure (so he wouldn't get cold), and left it for an hour the first time, overnight the second time.

Where should I go from here? Should I go back to offering live until it eats again? Or should I just keep offering the frozen now that I have a bunch? How many days should I wait in between offerings?