Phone Repair

I made a claim with MTN insurance for a device repair, which I did not receive feedback for until I sent multiple follow up emails. I had to swap a sim card to contact them because my phone's screen was blank. My claim was rejected because there was a different sim card in the device at the time of the claim. I don't understand this as I am not claiming for a lost phone which they need to replace, I just need them to repair my screen.