Change from windows 8.1 to windows 10 caused...

can anyone tell me how much the charge is to fix office Professional 2013 so it will run on windows 10 from windows 8.1 Office quit working when the upgrade happened. Took me awhile to figure out what was causing the problem, office worked just fine when I first got my dell running 8.1 OS, and a few months later it quit working, took until this morning for all the pieces to fall into place