Facebook's SMS account unlocker is not functioning

Has anyone else faced this situation? 1. Your account gets locked due to "unusual activity". 2. You try to follow the process to unlocking it via SMS verification. 3. You receive a text with an unlock code. 4. Attempting to use the unlock code within 15 seconds of receiving it - either via copying and pasting, or entering it by typing in the numbers fails because the code is "incorrect or expired".