I wouldn't put the following in correspondence to buyers ( nor in listings) as it contravenes ebay policy

"I have no control what happens once I post your goods, and I posted yours on the 19th October. "

Policy:

What not to do

You should not:

Say that you're not responsible for item delivery, or for ensuring that the item is delivered. For example, these statements aren't allowed:
'I'm not responsible for the item once it's been dropped in the mail'
'I'm not responsible for items lost in the post'
'Without insurance, I can't be responsible for items lost in the post'


http://pages.ebay.com.au/help/policies/selling-practices.html