DoCoMo — Not getting desired internet speed

Website:

m.tatadocomo.com

Recently I got internet data offer from respective company(Tata Docomo), which was read like this
"3 Ka Dum !! 1)Payiye Full Talktime At 30, 2) 750mb 3g At 75 Pure 28 Din, 3) Sabhi Mob Calls @25p/M, Pure 28 Din @ 22. Extra Benefit 48 Ghante Mein. Tata Docomo."

so I did second recharge of 75 which was for 3G but currently the internet speed which I'm getting is I would say even slower than that of they are giving for a 2g data pack.sometimes it is maximum upto 12kbps to 15kbps.well that doesn't look like 3G, and that too didn't work you have to wait for some time (actually a lot of time) till it gets active after making Data connection on.really frustrated.