Unable to correct an Address on an invoice

I have been struggling for months to get my address corrected on my invoices so I can claim VAT month end. This month I have received 2x overseas parcels again, which I paid for and can claim back VAT for but because of my address not correct and VAT nr not showing I can not claim the VAT. I have been complaining on face book twice already, every time with somebody phoning me, telling me that the problem will be sorted an well it is 3 weeks later, many emails and follow up's (where I have to mail or phone), twice filled in the form they have sent me, sent my proof of SARS Customs letter etc... AND still I don't have corrected invoices. This week I have revered our client in Germany to please rather make use of UPS since they can at least get my details correct and I can use the invoice. So DHL this simple matter is now costing you money internationally and nationally. Don't contact me if you are not the person that can change my address and add my VAT nr on my 2x invoices. I am done talking and e-mailing people that are trying to help me but actually don't get anywhere. Also I have to phone and e-mail the whole time trying to figure out what is being done and if there is any news. Not even basic customer service of letting your client know what is going on. I have been more than patient (3 weeks to be exact), I never spoke harshly or screamed on anyone but this is the limit now!! Can you get the addresses on my invoices fixed and add my VAT nr DHL....yes or no???