Trying to register the phone number using "https://graph.facebook.com/v21.0/398562980017039/register"

results into an error "Error code 133016 - Registration or Deregistration failed because there were many attempts for this phone number in the short period of time"

Documentation says, the error should clear in 72 hours since the phone number was prevented to register.! But even after 72 hours, we are getting the same error..

How can I resolve this ?

Thank you