pI've tried everything to get a freepost bag to return a not needed router and other bits. Can you h

I am a returning Talk Talk Customer. I have problems with the web site. First problem. I re-registered with my new acct. number but when I log on I get my old closed acct. Second problem. I've tried everything to get a free post bag to return the old router and other bits and pieces. It should be easy.....it's not. That's why I have taken this route.