Problem with boiler installation

[TeaChocKitKat]

We are having a lot of problems with the company that recently installed a new boiler for us. We think the way it has been installed invalidates the manufacturers warranty. Even if it doenst, we arent happy with the way it has been installed because its not what was agreed. Im not getting anywhere trying to resolve it with them. Sadly I've concluded that they are cowboys.
So I'm after some advice about what to do next. Do I contact OFGEM, the gas safe register (thankfully they are registered) or someone else? Ive seen lots of different advice on the Internet so I'm not sure qjat to do next for the best.

[celticmissey]

You need to take photographs of the installation asap and then contact Gas Safe. They have their own experts who can come out and do an inspection to assess the work carried out.