Horrible drain on property

Good day, for the last month my husband and I have been calling and trying to get hold of someone that can have a look at a huge horrible drain on our property. We are in the process of building and we want this thing remove. But we can't even get to the removal stage, because no one is willing to come out and have a look to see what is inside the drain. Therefore, no can direct us in the right direction. We have been going around in circles and this is becoming a joke. The drain is locked therefore someone needs to open it before we can continue the process. Instead of doing something every person we speak to plays a guessing game. Which is not helping at all. The drain is on my property. You will have no right to enter my property once the building is completed. Due to high crime and safety reasons.