My BSNL Broadband 850plan is very slow

I am using BSNL Broadband UL 850 Plan, starting speed is very nice when i used 8GB my browsing and download is very slownow my speed is 518.60kbps(DOWNLOAD speed in kilo bytes notation is 64.83 Kilo Bytes/sec). is it correct speed to my plan or not.plz help me some bodywhen i download any files its speed is very slow, why its happening

Are you getting around 60kBps while downloading ?

You are getting the correct speed according to your plan.

Yes

Then you have nothing to complain about. You are getting the right speeds.