we had a total of 160KG allowance but only 75 KG in the hold
Do I understand that you were therefore trying to take 85kg into the cabin?
we had 4 small pieces in the cabin that HAD to remain there
Does this mean that you had only 4 pieces weighing 85 kg that you needed in the cabin, or that 4 pieces were required and that you had more than 4 pieces in total? If only 4 pieces and they weighed 85kg, then they were certainly not small, unless they were gold bullion.
Somehow, I feel we are only getting part of the story here.