This problem usually happens because free converters do not structure vCard files properly. CSV data is stored in rows and columns, but VCF format requires specific contact formatting. To fix this, I suggest using TrustVare CSV to vCard Converter. It supports proper field mapping so each column like mobile number, email, and name stays correct. I had the same formatting issue when importing into Outlook, and this tool solved it. The software generates clean VCF output that works across devices and email clients.