All vouchers have Terms and Conditions attached to them....you should read them for each and ever voucher given by ebay.
One of the most annoying is the expiry date that can be overridden by the simple statement "or while it can be seen on ebay.au"......and then proceed to remove it from the site early.
When Plus was first introduced it was strictly no cancellation after the money had been taken from your account.
I believe there was so much outrage that it has now been changed. I suggest you read the Plus site and see what the current rules are.
