ADMIN PLUS INSURANCE

I am honestly not satisfied with the services i recieved. Firstly i claimed for insurance that i was actually paying for the past 3 years. During the time of the claim the response i got was that my claim was unsuccessful due because the claim was done after 72 hours of loss. Whereas what happened was that i realised I didn’t have my cellphone on the 19 of April which was the day i lasted used my phone, due because i was at home and i travelled , but just frew days after i arrived to my destination i realised I do not my cellphone and since i was from home i assumed i left it behind and I couldn’t claim at that point. But when i got home i did make a claim because by then i was sure that i no longer have my phone. Insurance told me that i should have claimed same day whereas i thought i left my phone at home. How am i suppose to claim for something that am not sure about? Please look into this. My refence number is 76749