Help required

[Rellum]

Hello all 

Newbie here nd would like some advice , I have a 07 A3 sline quattro 2.0 TFSI and replaced the rear bumper but it came without the lower diffuser. The part number on the bumper is 8P4807511 but Audi dealer cannot find it on the system so I'm searching to find what diffuser would be correct fit for my car. Attached is an image of the bumper for reference. I am looking for the diffuser and the plastic trim that fits on the top between the body and the bumper . Any help and advice would be highly appreciated