Ebay dont change addresses so hard to say why a previous address has shown up.
Ebay are closed until 8am in the morning
You can contact them here
www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
Weekdays lines open between 8 a.m. and 10 p.m.
Weekends they open between 9 a.m. aand 6 p.m.
You should always check that the address is correct on the item you have bought before you pay.
Collecting it yourself is probably the only answer as if the occupier of your old address receives the item then you would lose any Not recieved dispute.
If the item has been posted then there is nothing else you can do except hope the item returns to the seller and they are honest enough to re send it too you ( you pay the postage ) or they refund you when it arrives back
_____________________
We are just ordinary members trying to help.