It would fall on the other party to file the claim. It sounds like you have done everything you can to make sure they could have resolved this. I would leave your new phone number and contact information with them as a backup. People can file a claim for years after an accident so they may just be taking their time to get around to it. Cancelling your plan will have no effect on them filing a claim as long as the policy was active the date of the loss. For you state, they have 5 years
to file a property damage claim. I would make sure you keep all details of the accident, including any conversations and pictures to insure you're going to be filling a claim for the damage you actually caused.