Something wrong

This morning I was called to give instructions to the contractor building a project of mine (see pic). Going around I noticed with horror that the original infrastructure - that was in very bad condition and drippping sewage on the machines - was no more, and it had been replaced by brand new shiny HDPE piping, with the original factory smell. The new piping is physically excellent but the design is absolutely crazy and disfunctional. The management is unavailable, they will not aknowledge that they made changes or tried to improve the infrastructure since I was there and made the design (that was approved by the permitting authorities). I need to explain to them that the approved design related to the situation as I found it, and now there is a completely new situation, so a new design and new approval process is required. But my feeling is that they dont want to talk to me or the contractor o generally they hate having to deal with anything physical. They are managers, they have MBAs, they can type on computers, and basically they dont feel like it is their job to leave their airconditioned tenth floor offices. I feel they want me and the contractor to avoid bothering them. Basically, a new design is required, and it must include partial dismounting of the new system and addition of a new one. I am thinking how to solve the problem. They will not want to pay for a new design and for the additional construction work. They will try to blame me. What a summer.