if i post things and didn't get any upvotes and downvotes also can effect my account what will happen

Downvotes do not affect your Steem Power, only your reputation score and payout for one particular post.

How can i get my money back should i wait for 2 years ??

If you powered up, yes, you can get it back in 104 weekly payments. Alternatively you can invest in Steem Dollars, they pay some interest, and you can sell them any time.