it might be the straighter too which is not doing a good enough job of keeping your hair striaght. i used several brands before chi and none of them give me the result chi does. so maybe try to go back to chi. i have also recently started using chi’s silk therapy and it’s 44 iron guard and i think they work very well, maybe try them.
other then that, i don’t think anything can you u a lot. i am also from USA and my hair have no problem here after being straighten, they stay that way unless i wash them. but when i go to karachi, my hair just does not get straighten no matter what product i use on them.
another thing u can do is to go to a saloon and ask them to suggest something for you.