My mom was stuck on that level for a couple of weeks too. She came up last weekend for the kids' taekwondo tournament, and when she walked into the house, the very first thing she said was "I need you to beat this level for me".

I beat it in 10 minutes. Stripes+packages are the best for that level. Keep trying. You'll get it!
BTW, 5 minutes after I posted that I was stuck on 392, I beat it! Next time I get stuck, I am going to post it here. That seems to be good luck.