Problem in new car battery

I just purhcased a new Honda Accord, But due to some problem I was not able to drive it for 4 days. But after 4 days when I try to start my car, it doesn't start, I call the HONDA people they check and say battery is down. We have checked all the lights and everything was wswtich off.

We have been inform by HONDA that their might be a gravity problem inn battery this happen as we didn't use car for 4 days. Any they charge the battery again on Saturday.

But once again after a day when I try to start my car, again the battery was down. I could not understand how can battery down in one day and what it gravity problem. It is true that once you buy a new car you have to drive daily to keep you battery working. Because HONDA people ask me to drive every day 10 KM.

Can you please advise what should be the problem.