Although you did not specify what actually your problem is, let me try to help you with some obvious things that might have happened:-
1) All Vodafone numbers require verification from service centers, so if you have bought a new SIM card and have not verified it then it might be off due to it. You need to resubmit all necessary documents to your nearest retailer in order to restart your SIM card.
2) Or there might be some problem with your mobile phone. Try installing SIM card in other handset. Even if it is not working on other mobile also, you must contact customer services of Vodafone with other number. I am sure it will help.