6 months and STILL the wrong address

After all the phone calls and assurances after my last complaint on Hellopeter, my address has still not been updated on all my accounts. The only account that now has the correct address is the account i closed last week! I received my credit card statement yesterday and it still has the wrong address. When will this be fixed? It has been 6 months since i first changed the details, surely it cannot be that difficult.