Letter of demand received after a claim was author

I had an accident on the 9th of August 2014. I went to the police station together with the third party to report the accident. An accident report form at the police station. The form was signed by both myself and the third party infront of the police officer. Intergrisure assessed my car and authorized the claim. Later I received a call from Lewellen Nel from the Innovation Group and asking me that he needs the accident report from the police station, therefore I have to sign a consent form that he emailed to me. I signed and emailed the form back to him. After two days or so he emailed me again asking for me to write an affidavit. I told him that I don't see any point of doing so because the affidavit's content would not be different from what is on the accident report. About two weeks ago I received a letter of demand from Santam/Intergrisure stating that my claim was not valid as my report is different from that of the third party. I don't know as to which report they are referring to as only one accident report was signed by myself and the third party at the police station, and the claim was authorized based on that report. So, my question is how is Santam making two different