Dephaser pully nut tight ?

Hi basically bought a full timing belt kit,water pump,and dephaser pulley for my Laguna ll , put it in to local garage to get the work done only to get a phone call saying your cars ready but we never did the dephaser pully as the nut holding it onto the camshaft felt to tight and were scared we snapped the cam so never did it ...?. Any body ever have this problem ?