Anglian Safe & Sound Windows - Noisy!

We had Anglian Safe and Sound windows fitted to all the windows in our home, as we live next to a busy road. We had wooden double glazes units previously. The Safe and Sound windows have made hardly any difference to the level of road noise we can hear. We spent thousands of pounds and are completely gutted. When we complained, they simply blamed the trickle vents! If you have trickle vents already then you have to have them when you replace your windows. If Anglian's Safe and Sound windows are not compatible with trickle vents, then they are not fit for purpose in my opinion. I did a lot of research into the type of window to buy to reduce road noise, and read that triple glazing is not the way to go. You need 2 different thicknesses of glass to distort the sound. Anglian's Safe and Sound windows claim to have this, and yet they do not keep out road noise. I am now thinking secondary glazing is the only way to go. More expense - better get saving as Anglian took all of my window fund :-(