Facebook with a real contact centre ! You must be kidding! Facebook has over two billion users but only 60,000 employees. To answer the daily hundreds of thousands mails or phone calls, they would need to put the cafeteria short order cooks, janitors, gardeners, window and dish washers to work and yet it would no suffice.
Now, tell me, is you page presently online for everyone to see?
How do you know they are not sending the code to the correct number?
What was the exact message you got. Usually Facebook sends a message by sms or email.
Are you trying to connect through your phone or computer? Did you create your account with your phone?