Any way to outrank a site or pull down site?

Hi,

no malicious intention
There was 2 different groups, We know each other, recently they create a new website, similar niche as me and steal my services client and traffic.

One is using squarespace and the other is pure html which is harder.

Any way i can outrank them or pull down their site ranking or simple trick i could play them back?

How is that not malicious intent? You have no moral grounds to attack their site. Everyone has the right to be your competitor.

As far as outranking goes, a large part of the forums is dedicated to teach you how to do that. It's a pretty general question.