Standard Bank Refuses To acknowledge the flaws with their systems

2 Weeks ago, I lost a phone and the ********** that stole my phone managed to access my phone. After accessing my phone my banking app pin was changed and immediately after the banking app pin was changed money was transferred from my banking account. I reported a ***** case after I realized that the money was transacted from my banking account. Standard bank is declining my claim on the basis that I didn't report the phone to being lost to them immediately. I don't know how I would've reported a phone being lost while I don't have the phone to report with. An immediate payment was done immediately after the banking app pin was changed, I think that should've been flagged by their systems. I called the resolution center, they flat out told me there is nothing they can do.