What does the letter actually reject?
The insurer may dispute coverage, responsibility for the accident, the connection between the injury and the event, or the amount claimed. Those questions need different answers. Sending more bills will not necessarily resolve a policy exclusion; quoting the policy will not establish how a fall happened.
Mark the exact sentence that explains the refusal. Then identify any missing fact, cited document or response request. If the explanation is only verbal, ask for it in writing and keep a dated note of the call.
The aim is a focused response supported by records, not a longer argument that misses the disputed point.
