I can suggest the best way to split any oversized vCard files into smaller VCF files, You can try the WholeClear Split vCard Software . This advanced VCF split tool divides vCard files smoothly without any error or data loss. The tool maintains all VCF contact information like, name, email address, phone number, address, city, country, and zip code during splitting. Additionally, the software is compatible with both vCard and Windows OS versions. Plus this software offers a free demo and smoothly divide large vCard files.