I cannot see why you should go to court if you are willing to admit your mistake. Court should only occur where there is a disagreement. However there is no need to walk into the meeting and tell them about all the things you have been up to. Best idea is to go in, let the interviewer take you through what they want to talk to you about, you can then answer their questions as needed. Taking along any documents you might have may help you at the interview so you can show them the information - it is often difficult to get your point across when you are worried. Remember you are very likely to be treated fairly, so don't worry.

You are liable to pay the charges and if you don't you don't get the goods. I did not understand the bit about a company asking the driver to waive the charges. Which company, for what reason and why is the driver going to listen to them? If you want to contest the charges best action is let the driver take the parcel away. Sort it out with DHL and then get it redelivered, then everyone is up to speed on what is happening.