How to prove that someone crashed my car?

How to prove that someone crashed my car?
My husband was driving in his lane when a lady went into his lane made the car get out of control thank god he is ok. The problem is they both had the same insurance. The lady keeps changing her story and the insurance is not doing nothing about it they say as longest she says it's not her fault they can't do nothing about it. So we are stuck with out a car. Any suggestions on how to handle this?
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