water pump replaced/annual service

On 30/10/2015, I took my car for its annual service and my water pump was also replaced. I had to wait an additional hour before I got my car back after they had called me to tell me my car as ready. Since then I have been having endless problems with the water pump. I have to refill it every two days. This has never happened before. I have contacted the dealer the following Monday and explained to them what is happening and till this day,the water pump is still giving me problems. It seems that they do not know what they are doing or how to fix the problem. I have had no response from them, not even a courtesy email to let me know when they will be able to look at my car. I am very disappointed and disgusted with the service that I have received. I will not consider purchasing another Citroen vehicle again!