does insurance company allow to accept liability on your behalf?

Hi all
my wife reverse out of supermarket car park she look round it was clear ,she reverse out about 15 inchs, the other woman came down the wrong way behind other park car and crash into my wife, I phone my insurance give detail , less than 24 hour I haven’t give my statement or sketch of the accident. my insurance company phone me saying they accept fault on my behalf I tell them I am not accept fault , she said as long as you reverse no matter what it your fault, I then ask her if she reverse out and I speed up and crash staight in to her ,who fault is that she said the reversing party I think it a insurance scam , please tell me is it illegal for my insurance to accept so quickly on my behalf
Thank you