Appeal letter tol ife insurance company

Touchy subject but it is hard to write the letter myself. My father passed away within two months of getting his insurance policy. Since the time frame was short they do not want to pay out his full insurance amount but was willing to pay back his premiums. I need someone that is well versed in something like this it just upset me that insurance companies can get away with something like this. If you can do this I will provide the dates and the reason why they decline to pay out. Hopefully someone can help . I just need a good and tactical letter that can help. I have just gotten my lawyer but this has to be done first. Please if you do not have some kind of backround to help please dont accept this !!