Mate I want to play devils advocate. But read the conditions of your sale. Generally you buy the land/house as is. That's why you get all that time to organise building and electrical and pest inspections etc. But in saying that as well. Nothing sh*ts me more than people who cheap out and install internal flexible conduit underground instead of HD PVC or at least PVC. I hope you get a good outcome but don't be surprised if you don't get anything. Edit: instead of the old owners if you have an email from the real estate claiming the conduit is installed or all working etc, that's probably a better line to try for reimbursement.