Neighbor Nasty & Uncooperative?

My disabled next door neighbor takes their large dog throughout the day and evening for toileting on the same paved areas close to the front door of my apartment. Solids are removed but urine can't be. I’ve asked but they won’t find another spot -- even spoke to the owner who just blew me off. On warmer days the stench is awful. I have tried kindness, being helpful; even given gifts offering to help in every way. I even hosed down the area only for the dog to be brought right back! I am waiting to hear from mediation which is voluntary. Their attitude gives me reason to doubt any cooperation. I don't want to resort to tactics like putting down pepper. Please help!