ok quick update I replied and tried to clarify the problem, and made a couple of points, and I have just received this reply, the customer has now back tracked a bit and it is the neighbour that has a problem, and it is not the down pipe but an external drain so nothing to do with me.
Thank you for your quick response.
I understand that the points that you have made in your reply.
As far as I have been made aware by my downstairs neighbour it is the drain that is overflowing, not water overflowing from the gutter.
I am not looking for any follow up from yourself as personally I have not got any complaints with the service, I was only looking to make you aware of the situation following the angry complaint I had from my neighbour.
not sure what to do now, I know I am not in the wrong but the neighbour has put 2+2 and came up with 5
she still hasn't confirmed an address but I know who it is and her partner was at home when I did the job and would have seen me fill a big yellow container that I removed from site (rightly or wrongly).
any way at least I know it wasn't me so that's a relief