Facebook security code demand

hi....3 days ago while I was in facebook suddenly it asked me to re login. when I login again it asked me the security code which should have been sent to my mobile phone. I sent my phone number but I did not receive any code...I did it for several times but till now no answer...then I tried to recover my account and I did it successfully and it demanded to wait for 24 hours, after that time when I came back, it again asked for security code. I sent some emails to facebook group but I have not received any answer yet....what should I do now....
I would be grateful if someone could help me to solve it.