Unknown,
Sorry to hear you're having trouble. I'd stay calm and pleasant, and work with the dealer to get the rattly bits replaced.
And I'd go for a full refund on the parking sensors, or replacement with OEM ones and a solid "sorry" (like a couple of free services). Try to find out exactly what you have got, and get
HUK on your side. The sensors may have only cost £30 or so:
http://www.civinfo.com/forum/buying/...r-rip-off.html