Have NO idea how to clear goods from Customs

Our order was received in Johannesburg on the 1st May 2015. WE received an amount that we needed to pay for Customs Clearance. After inspection of the goods the invoice did not match the items and we were requested to get another invoice from our supplier which we did on Wednesday 6th May. Since the 6th May DHL clearance department have yet been able to obtain a custom clearance for us. Their system rebooks packages for inspection which is unbelievable, causing further delays, then their other system does not match up with Custom values and they cant get this right and then their manager or staff do not call you back. They promise to call and don't. I have called them at least 3- 7 times a day and always get a different story. I am shocked they have not after a week sent a staff member to Customs to rectify this ASAP. It has now been 13 days and still no goods. For a company that handles clearing of goods daily, they certainly do not know what they are doing.I am at a complete loss as to what I can do to get of package other than go to customs myself