Damage to my garden wall from cable laying

Hi all, the team that installed my cable to the house almost demolished my garden wall. It is now very precarious and we are next to a school - I am worried about it toppling onto a child. I have contacted customer services many times but they just misrecord the enquiry and mark it as resolved and closed. Over the last five weeks, I have contacted them by email, telephone and through the app but don't yet have a sensible response. Is there anyway of escalating this problem?