current campagnolo cranks are no longer square taper
https://www.campagnolo.com/US/en
Maybe you can mail, yours to an
authorized Campagnolo service center ??
5431 Avenida Encinas, Suite C ,
, Carlsbad California, 92008 ..
They will say if its repairable. and how much $$ it is, if they were approved to try..
...