ISP's have a max speed that they put on your line, this does not mean that they cannot increase your speed if they wish to do so, the excuse they use is that it is the max speed on your line that will give you a stable connection, I had this problem with BT, and had to chase them up to increase the max line speed, but since changing to Plusnet, my contract says up to 70mbs I am getting 68mbs, if you are using a VPN then the speed will drop slightly, obviously it all depends on how far you are from the exchange and where your nearest green cabinet is positioned