To return your items, kindly put everything into the return-envelope that was enclosed in the original delivery package.
The return-envelope is already pre-paid and has the return address written on it.
Keep it as flat as possible, seal it and then drop it off at the nearest post box that you can find.
Post Office and/or Post Boxes are available in your departing airport as well.
However, please note that the package needs to be dropped off before you pass the security check.
There will be no post box/post office or any delivery service available after you go through security.
Another option is to ask your hotel staff to drop-off on your behalf. In this case, please kindly remind the hotel staff to drop-off the package as soon as possible so that there will be no return delay charge.
Please let us know if this does not help.