Claim against me 2 months after the incident

hi all as this is my first time on the forum and i have a question about a incident which is involving myself and another party.

on 5th Feb i apparently hit a stationary car when parking in a supermarket car park and a witness claimed that i have damaged the other parties car so the police came out on that night to check my car which had no damage on it at all, police asked the relevant questions as they do to see if your licensed and insured. The police officer went back to his van phoned the other party and witness to tell them that i have no damage on my car and that would be the end of it.

I received a letter yesterday saying that they have started a claim against me 2 months later than the incident date. I have phoned my insurance and explained to them exactly as above i have asked what evidence they provided and all they have provided to their insurance company is my registration number and it seems a bit weird after 2 months they now just claim against me is this a common thing?

I don't know what else to do as this is my first incident with insurance companies

Thanks
Jamma