Convert SPBA to VCF

The only program that can reliably recover or export data from .spba files is Samsung Kies, so this is the software you need to use if you want to export the contacts from the backup file and save it as vCard file, which is what spba to vcf conversion essentially represents. It is very likely that you will need some particular version of Kies, because some later version might not support older version of backup files anymore.