Urgently need impact cushion for baby car seat

Grr, I've just bought a Concord Transformer pro car seat from baby-online.fr (over 200 euros) and it's arrived without the impact cushion. My baby is only 10kg so I need this urgently but the company is not answering the phone or replying to my emails! You can't buy them separately so I was wondering if anyone has one they don't need (what do people do with them when their child can start using the seat with the car's belt?)