Ugh hair extensions help?

i bought some that were fake and you clip them in and they were curly so it tried straigthening it and of course it melted off and now i found out that only the real human hair ones can be straighted. FRICK. the fake ones i got were like 50 dollars and there werent any that were straight at Sallys. so does anyone know a secret that can make my curly fake extensions to be straight lol cause they cant be refunded D: im sad.