[BNM] Web project dispute-impasse-mediation?

[Yan_fit-pixels]

Hi all,
Wondered if anyone had experience of resolving an impasse regarding an 
ecommerce site/content management system?
Sometime ago we took on a project to redesign and redevelop a site for a 
fitness company.
We're designers so hired a recommended third party contractor in India 
for phase 1 build which was basic ecomm backend and GUI.

Eventually got this finished although was really financial disaster for 
us due to micromanagement hell and we agreed with all parties that next 
phase (more sophisticated backend operability) would be exclusively 
between the client and developers only.

Things have not gone well and it appears they are now in dispute over 
how the client feels the system ought to operate and the amount of work 
already put in by the developers according to the spec.

We can see it from both sides but can't do much else.

Has anybody experience of using a third party mediation service at all 
in this kind of context?
We don't have much involvement with the website apart from making 
updates to the site in terms of design and adding new products but we 
would like to see it completed to everyone's satisfaction.

Thanks
Yan