Impossible to get hold of - urgently need to get hold of them and they don't answer

I have been calling TNT ALL DAY today with a total of 2 answer and transferred calls. No one ever picks up the transferred call. It just rings and rings. I urgently need a package of mine that they have and I am trying to get hold of them to send me the customs invoice so that I can just pay and get my package. Service is absolutely shocking.