I have curly hair that grows down not out (I don’t have an Afro) and it’s quite long. I’d straighten it quite frequently if I could, but every time I do it doesn’t stay dead straight… It goes a bit curly and on the top it goes quite puffy? Is there any products I can use to try and stop this? I’ve tried using hairspray and loreal non frizzy serum but it never works with my hair! Help?