Don't worry
dG-or
I have hah it one month ago which buyed in the Postoffice
dG-or
I guess these stamps should be selled in all of Postofficem in china
dG-or
or look for it by youself in Hong Kong 'Postoffice
dG-or
as far as you said if buy it in the internet
dG-or
sorry I do not know you can try
dG-or
good luck