My Inspiron 15 5575 shows a black screen. My service center won't repair it despite me having a warranty

My laptop doesn't boot to OS, I took it to my service center and they said I need to upgrade my warranty to Premium Support, subsequently I phoned dell's helpline (which is rather frustrating because you can be held up for a long time) and asked if that was the case and the nice employee over the phone said that I already have accidental damage service and next business day on-site warranty which covers me well enough. Yet the employee at Dell's service center keeps asking me for written proof. Someone please send me the actual details. I have a lot of work to get done in this lockdown. Please communicate about your warranty details clearly to your service vendors. Help me someone

P. S My Service Tag is . I am afraid Dell is deliberately trying to push dates beyond my warranty cover. This is a terrible experience.