Sub grade windscreens - poor service

I bought a windscreen on 7/12 from Sump windscreens. I realized now when the rain started that the rain sensor on the “ new” windscreen is not fully functioning. It only comes on when I start the car but when I drive it is not working. This after I was told I have to put in a windscreen with rain sensor! I had major issues initially with Sump when I had the windscreen installed(see complaints logged on 7/12). Your guy at the counter told me that hopefully the windscreen will arrive without any small cracks or anything and guess what... a chip has appeared on the windscreen however that is not the Main issue, the issue is the rain sensor on the windscreen that is not working!