When you try adding a call forwarding number to your account, you may receive an invalid number error, or an error indicating that the number is being used by someone else.
The reason for this error is that a number can only be used Once within our system, this includes Fongo Mobile, Fongo World Edition, Fongo Home Phone, and FreePhoneLine.
If you receive the error, it means you (or someone you may know) have already added that number elsewhere within our system on another account, you must remove the number from your other account before you can add it to a different one.