You can find the Telugu dubbed version of "The Voyage of the Dawn Treader" on various online platforms. However, I must advise you to be cautious when using third-party streaming sites like Movierulz, as they may not always provide official or high-quality streams.
I strongly advise against using torrent sites to download copyrighted content. It's not only against the law, but it also poses a risk to your device's security.