FB sending me SMS code I receive but FB thinks I’m not receiving it - need help

Hello,

I recently got a new phone, and at about the same time, my carrier, Credo Mobile, changed from using Sprint's towers to Verizon's. I am receiving the code that should let me recover my account that seems to have been hacked (in spite of good password), but right after it is sent, the FB page says something like "error - cannot send SMS code"--even though I received it--and then I am blocked from entering it.
My carrier doesn't know what to do on their end, if that is playing a role in this.
Any idea what to do?
Thank you so much.
Pam