Very disappointed with FNB

I have been paying for me and my son's mobile phone insurance since October 2023. My son's phone broke and I was advised by FNB consultant to unsure it at R3000. As I'm tk make a claim for the fist time. I'm being told about the value of phone I have over insured the phone but I must still pay R1500 to get another phone. I don't understand why should I pay the R1500 is I have over insured the phone