I have 750 Unlimited plan from Bsnl.....[I had change it from 250 to 500 to 750

]
I have got a not so good speed of about 60-70 kbps...
But a few days back suddenly my speed got decreased to 30-35 kbps....
I thought it was because of some virus or malware, so I formatted my computers's entire harddisk after scanning it with many antivirus and anti-ware softwares one by one [




But of no use



]..
I booked a complain and they took my modem and they return it the next day saying that the problem was from the exchange..
I plugged back the modem and still no


use...





Please help Me.......................
h t t p : // w ww .my broadbandspeed.co.uk/results/30657301
. png
The Above is the URL of the image of the speed test that I ran just now.....Please copy it to your address bar and cancel the spaces .... I am not allowed to post images as I didn't complete 15 posts......