Just wanted to know if this is some sort of scam?

oki so i got a call at 4am from an unknown number and the caller rang twice, i didn't answer the first time coz it had just woke me up, so they rang again and i answered and it was the women from 0800reverse but when she said someonee named... wants to speak to you the person just mumbled something not a name so i didn't accept coz i was tired and dint no hu it was, but i later realised you cant make 0800reverse calls to mobiles so i was just wondering if it is some sort of scam just incase it happens in the future