Building works

Hello Guys. Wishing you all a very happy lockdown - that is to all those who are still in lockdown…
… also just popping into the forum to share some problems…
It was great, approximately 10 years ago, when the local authority sorted some building work around the house so that my mother could stay at home. The works included installation of a walk-in in shower upstairs which I have already had converted back to a bath as it there were leaks. Also wheelchair access was installed to the front of the property so that I could take Mum out - but, soon after installation, it became clear that, during heavy rain (or hail), water would get in under the door and flood the living room. I contacted the authority and they denied that it was a problem. Following a heavy hail storm I contacted the authority again but they replied that it is too long since the works were completed for them to take any responsibility.
Shortly before lockdown I contacted a builder who called and quoted for some works to correct the problem but he also recommended contacting the authority as they were responsible for the work and I replied that I have contacted the authority and they denied responsibility. As lockdown eases I suppose I will contact the builder again to get the mess corrected. Has anyone else experienced this sort of problem?