FNB pre-approved loan glitch has ruined me

I had a pre-approved loan on my FNB banking which led me to bid for a car at an auction knowing I can access those funds to reach the bid amount.

After winning the bid, I went on the app and filled out the details, on the last step I got logged out. Now when I log back in it's gone and I am getting rejected.

I am now left stranded with a commitment to pay an amount I don't have. Failure to pay this in the next 24 hours I will incur charges of over R20K and lose the car.

I'm crushed. I have tried family and friends and no luck but this system glitch has completely ruined my finances. Please help?