Are clients paying real penalties and fines?

I have corresponded with 19 mails(from mid May 2020) to DHL already, requesting a letter(or any official paperwork) stating that I have paid a penalty to DHL for the parcel being under-declared by the supplier on the invoice that accompanied the parcel. I need this paperwork to claim back the penalty fees and other costs incurred due to the under-declaration mistake by the supplier. The supplier will only look at my claim if I can provide them with paperwork stating that I have paid a penalty, and that it was for the under-declaration, and for any additional costs incurred. The supplier is not convinced that I have paid a fine due to the descriptions on all the paperwork I have received from DHL refers to the fine as “Possible Penalty” or “Provisional Payment”.

If I have paid the fine as indicated by DHL, surely it is no problem just sending a letterhead or a invoice stating that.

I has officially been stated to me in an e-mail "There are no additional documents that we can issue accept what I have sent to you previously " (which did not mention any fine or penalty, only possible penalty and provisional payment)

I have also communicated with the supplier, and they are prepared to look at the claim if the paperwork states fine or penalty paid. I have requested DHL to communicate with the supplier, but the answer I received was "Please understand that DHL is a Clearing agent and cannot intervene between you and Banggood’s , that’s is why I communicate with you so you may speak to your supplier".

Who instructed DHL to be my clearing agent? is the question I asked, but have not received any response on that matter. I would have preferred to clear the parcel myself, or use another clearing agent that has cleared for me before.

I am now at a stage where I have purchased an item on line, and up to date have paid more than double to get it released. It states on DHL documentation that I had to pay or it would have accumulated costs for warehousing.

I make the assumption, taking in consideration the facts at my disposal and the refusal from DHL to supply me with an invoice or official paperwork reflecting the word fine or penalty, that there never was a fine, or the amount was less than indicated.

The only reason why DHL would not want to state what you have paid for is they never had to pay or did pay it to customs themselves, or it was inflated amounts.

It is a disgrace that a large company as DHL has the power to just leave matters and know that the average customer cannot fight them legally due to costs.

I am totally disgusted on the service received.