I can not understand how a company as big as DU fu...

I can not understand how a company as big as DU functions so poorly.
I'm only giving 1 star as that is the lowest I can put.
I'm trying to receive previous bills, something you would assume to be very simple. After visiting Du branches FOUR times and being told different information each time, and emailing FOUR times and receiving conflicting information to what I was told in the shop, I am still no better off.

I'm not angry, i'm disappointed, I'm lying, I am actually pretty angry.