shocking client service

Having started new business importing crafting supplies I was excited to partner with DHL who I have heard very good things about, unfortunately my experience has been awful, first stock shipment I had was held up at customs, I was asked to contact a department for a license to clear the stock, despite me telling them that it was an agricultural department dealing with exports, they insisted, after contacting the department they told me to, that department gave me a letter stating they do not provide licenses or deal with imports, the shipment was then cleared after a delay a runaround and a waste of my time. Last week I was notified that my new shipment has arrived, carton 1 out of 3 was delivered without a problem, carton 2 had the incorrect postal code put on by the supplier, I phoned in on Monday and spoke to Agnes who assured me that an email would be sent to correct the address, I too went on the system and corrected the address, today it was again sent out to the incorrect address, after phoning in, holding on for over 20 minutes for a team leader was put through to Patrick, what an awful experience, after explaining my issue, which I'm not sure he even understood, he kept telling me the supplier put the wrong address its not their fault, he kept repeating this despite me telling him I have called in twice to have this corrected it still has not been corrected his reply was again the supplier put the wrong address. my issue was not resolved and I don't know how to get this sorted out, nobody I speak to can actually help me change the address. I don't understand how only one of the cartons has the incorrect address and why I cant get this fixed, I have clients waiting for stock and this is costing me money. Terribly trained staff. As I'm writing this I am still on hold for a manager or team leader to assist me, i have been on the pone in total almost two hours with no luck. very disappointed and despondent at this point I just don't know what more to do to get help