Airtel — slow speed connection

I chosed the 499rs plan in gwalior with speed upto 4 mbps though i always gets the speed till 500kbps or slower than that... also when i asked them about my plan they told me its upto 2mbps speed then why showing 4mbps on the site... and when i asked why my speed is slow they told my house is a bit far okay i understand that but then why show 4mbps on the site showing gwalior huh???
i live in gwalior and i dont get the speed told by airtel... if the problem is that my house is a bit far then write it on the site that speed may vary though locations...