Worst product quality, no proper diagnosis of the problem

I bought this laptop 2 years ago and since then Dell has left no stone unturned in bothering me. Their technical support is a big FAILURE. They expect us to be on call with them and perform diagnostics for more than 5-6 hours.

In last 1-2 months they've changed two major parts heatsink and motherboard but the problem is still same.

Now I'm trying to reach their technical support through phone, but the agents are just disconnecting the calls. I'm told talking to the manager is not part of their policy. Can't even request a call back from the manager.

Still my laptop is dead and so are my hopes from Dell.