2018 Sante fe sport dash lights up like a Xmas tree and won’t let me put it in gear

Car was the dealer demo bought
new off the lot. 8000 miles. Parked in
my driveway and one morning,
though it started up the – lit up with
various icons and dinging bells and
wouldn’t let me put it in gear. After
sitting another hour, I tried it again
and it suddenly worked. Hyundai
serviced couldn’t get it to act up
again and so returned it to me
without doing anything. After driving
it eight days and 100 miles later, it
began doing the same exact thing.
Hyundai has it in their possession
again and said they can’t fix it unless
it acts up while they have it. Help!