What happened::
I was going to sell a $300 google cloud account for $30, I gave the account him for to check., and he blocked me without paying. (I know it's because of my inexperience.)
Can you not recover the account? at least change the password after he stop replying and pay you for the amount. I rarely seen a seller got scammed by the buyer here. Anyways, you should be more careful next time and serve this as a lesson.