Old att # forwarded to new att #?

I just created a new cell # with my current att account but my messages (just sms, it seems), aren’t going through now.  iMessages are working fine.  

Also, how can I have my old # to forward to my new #?  I tried to do it in settings after the fact but it’s not working.  I am assuming I should have done the call forwarding prior to restarting my phone to have the new # set up w/ my new #?  

Is there an easy way to fix this without having to sit on a call w/ att?