Sorry to hear about this. Anything like this is extremely stressful. Given that there is some video evidence and the other driver ran off, it is highly unlikely that you will be held accountable for this claim, as the other driver rather sealed his guilt by fleeing. I suspect that they were under the influence (more likely to be drugs these days) and fled to avoid being tested. If the other driver genuinely believed that it was your fault they wouldn’t have run off, a point which DLM will no doubt make (if they do their job properly).