Add Documents To Zip

I am passing multiple document to smart service and it successfully creating zip of it. 
But, When i Unzip the folder the extension of the files are getting lost. Hence I am not able to recover the format of the file.

Can you suggest the solution?

When you are setting the path for each file, Please provide the file extension to the path, so when you will unzip the file in the system you will not loose the extension

ecample

1. intro\file.txt  (text file)

2. intro\file.csv

When you are setting the path for each file, Please provide the file extension to the path, so when you will unzip the file in the system you will not loose the extension

ecample

1. intro\file.txt  (text file)

2. intro\file.csv