90+% of startups fail. Just because you made it with one doesn't mean you'll make it with another. So many things can go wrong. Even if you do everything right, you're still rolling the dice.

Do your friends and family understand that they have a very high chance of never seeing that money again? If you value your relationship with them, give the money back.

VC investing is not for the faint of heart. You probably convinced them to invest because you've done it once, and were decently successful -- but not successful enough to have a seed round for your next one.