Need to know which multi point mortise to buy

Sorry to hear the 82-265 didn't work for you. You can view our Return Policy here. As far as the correct mortise goes for you, take a look at the 82-260. This is a more 'recessed' version of the same mortise, with 12" spacing between the screw holes. I can't guarantee this is what you need without seeing your original mortise lock, but review the listed dimensions and see if you think this would work for you.