YODEL’s phones are all off when I try to call

So my parcel was meant to be delivered today been in alday went on there site to chat to someone online to see where it was they said to ring his number so i did got an answer machine as appz drivers have to have their mobiles off so they wont get calls or texts got off the chat 10 mins after only to get a email to say we tried to deliver and left a calling card well abit convient as i dont have a calling card and it says to ring the his numb well thats abit stupid since they cant pick up since their phones are off