Tree and pavement dept ignoring my 6 reports of damage from tree root invasion to my large front wall

Have made report every week/ten days of progressive crack to my large front wall which is being damaged by tree roots from nearby tree which has already clearly broken adjoining pavement to my wall and caused a now very visible crack to my front wall from base to top neatly joining the pavement crack which started at mid point of pavement . I've also contacted both my councillors with no real response. Pavements team acknowledged reports but no actual response . Tree /arbiculture team say they need pavement team to inspect although fixing pavement will not fix actual problem or stop damage up my property which if collapses / needs repair will be costly. Wall faces busy through fare of young school children to neigboring St Luke's and busy stop. Who is liable if wall collapsed on pedestrian ? I have now sent 6 reports via the council system of reporting .