Have you made a purchase on the account recently with a valid credit card? I had to wait a couple of weeks for the open chat option to be present in the game. If you ask support directly, they'll look into it. You do have to make a purchase before getting the option though.
um im coming back too wiz and I’m 18 now but I can’t get open chat because I was underaged
Welcome back! If you are 18 now, have made a purchase on your account with a credit card, and your Birthday is correct on the account you should now have the option on the "Parental Controls" tab under the "My Account" section. Simply check "Open Chat" to "On."
If you need further support, please contact support :).