Poor management of customer complaint.

On 1st March we had a gate installed as security measure with our sliding door.From then to date ,whenever it rains ,water is pouring in where the gate has been installed at the holes that was drilled.This is something that never happened before ,from the day the sliding door was installed. I am now being referred to the builder in question,as a lintel was not put ,when the sliding door was fitted.Due to incompetence of staff ,who did not identify the risks involved, when they did the drilling,we were not advised of the unsafe practice to have a holes drilled and a have installed .In stead work was completed, and balance paid.If we were informed of the risks ,we would have opted not to have the gate installed. The area in question, is a Daycare for kids,and poses risks to the kids.