Hello Zain,
Thank you for posting your query on Microsoft Community.
As per description, you like to resume the partial download using edge.
I would suggest you to follow the suggestion provided by vianyil replied on August 18, 2015 from the link given below and check. These suggestions helped many community members.
Refer:
http://answers.microsoft.com/en-us/windows/forum/apps_windows_10-msedge/edge-wont-resume-downloads/2504658a-67eb-41c6-9845-2c4368277c7b
Hope this information is helpful. Please do let us know if you need further assistance with Windows.