sim card activate

Hello! I have been using Nos since day one i got to portugal and after awhile i didn't charge it with money i tought i can prepay it in ATM  but it never did ,maybe i mistaken something in the process . What matters to me now is to get my sim card activated because it is important for me . I have already called that number they gave me in shop and whenever i enter the nif it says invalid !! I don't know what to do next since it's an important number that i never changed !   I hope someone will reach out to find a solution for this , it's been more than 2 weeks now trying to find out how to reactivate it.!