Some company give guarantee about to show your website on the first page into short time period and even they can do this. But how is it possible into short time period your website on top and you pay lots of amount to them.
Google updated algorithm time to time which affect the website ranking. Black Hat SEO only focus on the website ranking not on the visitor view point. Some violate the SEO terms of guidelines and result of this Google penalizes them.
Don’t use this technique other wise search engine will block you or penalize your ranking of pages. It’s the only way to get the success for short time not the permanent.