I am not discounting the possibility your appliance is faulty, but from the description you give it is not obvious the sensors are faulty - you tell us the new machine takes 8 hours to do a job the old machine completed in 3. That being the case - that the job was completed, there is nothing other than the time it took to raise doubts about its efficiency, unless the power the new machine it consumed were greater than the old.
The dissatisfaction you have is the efficacy of the new appliance in comparison to the old one. In particular the time it takes for the machine to complete its task. Is the machine taking longer than it's specifications claim?
The difficulty is, you are not comparing apples to apples. The new machine employees a different mode of operation, and that can easily mean the way it executes and completes its task will also be different. It is also possible as part of its "green" criteria is what defines the completion of a cycle may be differnt to the old machine.
All these differences could easily change the time it takes to complete its cycle.
I do hope the service team can establish if there is fault or not with the new machine and resolve things satisfactorily.
If it took 1/2 hour longer per load and washing was dry, we could live with that. We doubt very much if the machine is faulty however it is not doing the job within a reasonable amount of time. I think nearly a whole day to dry washing is a bit over the top and unreasonable. as said even Which who do extensive in-depth tests came to the same conclusion that some washing is not dry at the end of the cycle.
We would be happy to change it for a machine that is not so energy efficient but dries the clothes properly within a reasonable amount of time as at present our laundry day is not two days instead of one so OH not happy.