@Theresa_2068371 Sorry, but you haven't really given us a lot of information here.
Does your account dashboard show that you have an active Smarty plan? Do you have signal bars showing on your phone? Are you in the UK or EU? If you are outside those areas, have you got credit on your account to pay for calls? What happens when you try to call someone? Have you checked the network status checker to see if there is a mast problem where you are?
I hope you can see the type of information that would let people help you.
