Details of the two North Somerset councillors for Yatton Ward (which includes the parishes of Kenn and Kingston Seymour) can be found at http://www.n-somerset.gov.uk/ The two councillors jointly represent the whole Ward.
Each parish councillor represents a 'ward'. Roughly speaking, Claverham Ward is the village of Claverham, South Ward is Yatton south of Chescombe Road and Well Lane, North Ward is Yatton between Chescombe Road and Well Lane and the railway line and Horsecastle Ward is Yatton north of the railway line. You may find it easiest if you contact councillors representing your ward but you do not have to.
Yatton Parish Council has adopted a Code of Conduct dealing with the conduct of members of the Council when acting in that capacity. Details of how to make a complaint about the conduct of a councillor, which must be made to the Monitoring Officer at North Somerset Council.