Disappointing Service

Have tried to contact them for two months to come to an agreement to complete there project to replace our windows to no avail they do not even answer us back and this was after i had a meeting with them in January where i said that things needed to be fixed and i showed them photo evidence. There windows are still leaking after 3 years of them repairing them. They have put in so much silicon is should not leak but it still does.