It’s really annoying when your Sonim phone won’t let you delete contacts. Oh, you can delete some, just not the ones you want. I finally got fed up enough that I figured out how to do this.
First you need to navigate to the applications menu.
Next navigate to the Backup and Restore app.
Choose backup. You will need to have an SD card installed because that is where backups get written.
Now you need to have your phone connected to a computer and file transfer enabled. The backup is found here.
The file name will be “contactbackup.” Make a copy then use your favorite text editor (not a word processor) to edit the vcard data file. If you’ve never seen one of these text files, they are ugly.
Each “card” is bounded by BEGIN:VCARD and END:VCARD. The format of the N: line is last;first and God only knows after that. Not every contact manager will support all of the vcard tags. You can find a list of them here.
When you have made all of the changes you want, save the file. Now comes the non-obvious part.
On the phone choose restore.
You can’t delete that stuff, but the restore option can. If you find you made some kind of typo simply edit the backup file and restore again.