Bad Nissan Navara experience

Took car for Clutch replacement at mac Carthy Nissan Woodmead, the clutch repair i believe went well, but on closer inspection by dealer it was found that the firewall around the clutch master cylinder was torn and needed repair, the Navara was never in an accident, am the original owner. I believe this is then a manufacturer problem, mac Carthy Nissan just fobbed me off and are leaving me to carry the responsibility to have the firewall repaired at my expense, they mac Carthy Nissan did not even offer to ask Nissan if this is not a design defect and if they could at least share the expense. This is the 2nd Nissan double cab i have owned and have generally had no complaints until now, this incident has left a sour taste and i will never recommend or brag about Nissan or buy one going forward.