Tax requested to be paid on lost personal do***ents !!!

On my way back from Europe in January, while in transit at Frankfurt airport, I lost my old small change wallet with three personal documents: Driver's licence, Bank Windhoek ATM card and NMC medical aid card. I managed to get in touch with "Lost and found" office at Frankfurt airport and they told me that lost wallet can be either collected or shipped within three months. After almost three months I opted for my lost wallet to be shipped. I paid requested 70 euros on 12 April 2016 to Frankfurt airport-lost and found to send me my documents. On 18 April 2016 I have received an sms from DHL in Windhoek that my shipment from Germany is on hold for payment of import tax at DHL of N$ 1,318.82 !!! I have contacted DHL Windhoek to object the import tax as I'm sure it should not be in place for LOST PERSONAL DOCUMENTS. As been advised by DHL employee Elsabé van Staden I placed an official complaint by writing a letter,submitted copies of all do***ents required as well forwarded all correspondence with Frankfurt Airport regrading my lost documents. I was then told the issue will be transferred to Tax department. After over two weeks with Tax department, issue was returned back to DHL, for them to solve it. It is still with DHL, almost a month since I was told my shipment has arrived. They are trying to convince me that it is not their fault that all this happened but I'm 100% sure that it is. They said that sender wrote that value of shipment is 150 euros, which I don't know where it came from. Anyway, from the beginning I asked them to open the shipment and confirm what is inside. If they base their import tax charges on the value written by sender,that means that anyone can import anything worth N$ 1 million and not to pay a cent on tax because the value declared is N$ 0. Does this makes any sense ??? Very frustrated at the moment.