user28012: I am new to Bitcoin. So, I downloaded the Windows Bitcoins software from the official website and used the "request bitcoins" option to request bitcoins from my exchanger.
My exchanger charged me $20 and told me he will send me bitcoins corresponding to $20. But even after 18-20 hours I didn't receive any bitcoins.
Additionally, the Bitcoin software is showing synchronizing with network : x years xx weeks remaining. 
What should I do? Should I wait for the synchronizing to complete or file a complaint against exchanger?

user5757: Yes, wait for it to finish synchronizing. You will not see your coins until it finishes.
(Note that the time shown is not the estimated time until completion; it represents the age of the old transactions currently being downloaded. Depending on the speed of your computer and internet connection, you can expect it to finish in a few hours to a few days.)
In the meantime, you can enter your address in a "block explorer" site like http://blockchain.info to check whether the seller made the transaction as agreed. (This is safe; your address alone cannot be used to steal your coins.)
If you don't want to download the entire block chain, you can use a different client such as Multibit, but you will have to import your wallet.dat from Bitcoin Core into your new client software. Its documentation should explain how to do that.

28012: <p>I am new to Bitcoin. So, I downloaded the Windows Bitcoins software from the official website and used the "request bitcoins" option to request bitcoins from my exchanger.</p>

<p>My exchanger charged me $20 and told me he will send me bitcoins corresponding to $20. But even after 18-20 hours I didn't receive any bitcoins.</p>

<p>Additionally, the Bitcoin software is showing <code>synchronizing with network : x years xx weeks</code> remaining. </p>

<p>What should I do? Should I wait for the synchronizing to complete or file a complaint against exchanger?</p>
 5757: <p>Yes, wait for it to finish synchronizing. You will not see your coins until it finishes.</p>

<p>(Note that the time shown is not the estimated time until completion; it represents the age of the old transactions currently being downloaded. Depending on the speed of your computer and internet connection, you can expect it to finish in a few hours to a few days.)</p>

<p>In the meantime, you can enter your address in a "block explorer" site like <a href="http://blockchain.info" rel="nofollow">http://blockchain.info</a> to check whether the seller made the transaction as agreed. (This is safe; your address alone cannot be used to steal your coins.)</p>

<p>If you don't want to download the entire block chain, you can use a different client such as Multibit, but you will have to import your wallet.dat from Bitcoin Core into your new client software. Its documentation should explain how to do that.</p>
