What communication service are you trying to contact? http://goo.gl/w8OehW
There are different time repply according to whom yu want to contact with.
-Repply from a supplier
-Repply from a client
-Repply from Alibaba custom service (email. chat, complaint, etc)
-Repply from Aliexpress custom service (refund, complaint, etc)
What kind of repply are you waiting for?
About a week