Dell Inspiron 7391 2 in 1, BIOS issue

Hello Team ,
I purchased my Dell Inspiron 7391 2in 1  from USA .
It was having very frequent network issue when I brought it to India 
It asked me to update BIOS via popups . I hardly used the laptop for a week and sum total of less than 24 hours.
I upgraded the bios as suggested by DELL. I have put the laptop in charge while upgrading BIOS. 
The BIOS upgrade never completed. Whatever BIOS was working it got corrupted . It is stuck in one screen of BIOS recovery and it never comes out of that. I have tried all the options shown on screen in there and all suggested by the DELL on the websites but none seems to work. 
I have tried Recover the BIOS, - it does now work and returns to the same screen.
- Rollback to previous BIOS-  It failed as giving message that it cant be downgraded.
Load Bios default - not working
Then tried booting with USB key , not working
Not able to go to the boot menu (F2) or F12 - its redirecting to this same screen with BIOS recovery option.


I carried it to Service Centre in India after transferring the warranty to India. They told they have to replace the motherboard and I have to bear the cost even without looking into it and blamed me directly for it.
Nothing was  mentioned in Dell web site while transferring the warranty to India that it is invalid and have to buy an international warranty.
While I am quite sure there was no fault from mine side, as I have seen similar issue in this forum with the same model :
ex. https://www.dell.com/community/Customer-Care/Inspiron-7391-2-in-1-not-starting-escalation/td-p/7645674

I then thought when I will return to India I will go to service Centre in USA, but it has been 7 months since then and I have not been able to return and stuck here and now its warranaty is also about to end in a month.

It has been very frustrating experience that after buying such an hefty priced laptop , the laptop did not even last for 1 week,  the  network issue started coming  with it  and owing to their suggestion upgraded my BIOS  and need to pay to fix their mistake 
It has been very frustrating experience for me  with Dell Laptop , dell customer care, dell service and would never ever think of suggesting any one to buy Dell as their after sales is one of the worst.
Please provide me what all alternatives I have to make the Laptop working without spending hefty amount.
I dont believe the service centre who even without looking at my laptop asked to replace the mother board.
The reason being of not believing service centre  is that there are many solution given in the Dell websites where they have given multiple ways to recover from the corrupted BIOS. Thought most of them I have tried but does not seems to be working.