Delayed tracking information

Tracking status on the fleet platform is delayed in the afternoons and not up to date - sometimes by 30 minutes, sometimes by hours. This means you cannot see an accurate location of your fleet because the system is not updating. Only happens late afternoons in the week. I have tried every possible avenue to get through to management, but the call centres just play dumb and shield management from dealing with the problem. Same result on multiple phones, computers, internet connections etc etc....just in the afternoons on their platform.