Late and lack of responsibility

I went in on Thursday to order an overnight collection of documents I had sent up with them on the Tuesday. The woman helping seemed like she was filling in so when she didn't ask for payment I prompted her that I needed to pay. She said no I didn't because it was part of previous delivery. I knew it was not and tried to explain but she assured me all was OK. The next day I got a call to come and pay. I went in on Saturday morning to pay and found out that the pickup for the documents I needed urgently had not yet been put through due to non payment. That is the lack of responsibility. Your fault...don't make the customer suffer for your mess-up. So I went to go collect today and apparently my overnight delivery will only be here on Wednesday. That is 1 day short of a week for an overnight envelope!