If your goal is to just get names and phone numbers from Numbers into Contacts you don't need to mess with CSV and vCard. Often a short script will be quicker.
For example, say you have your Numbers table like this, three columns, with nothing in the Header Row:

... Then the script below will add these to Numbers. (No scripting knowledge needed to run).
- Copy-paste script below into Script Editor (in Applications > Utilities menu).
- Click anywhere in the Numbers table with the names and numbers.
- Click the triangle 'run' button in Script Editor.
First test with a few to make sure this is working as you want.
If your table is set up differently, for example with first and last names together in the same cell, then the script would need some small changes. If you also have address information you want to add to Contacts, that is also quite easy to do.
SG
tell application "Numbers"
tell front document's active sheet
tell (first table whose selection range's class is range)
set vv to (rows whose first cell's value is not missing value)'s cells's value
end tell
end tell
end tell
repeat with i in vv's items
my addToContacts(i's first item, i's second item, i's third item)
end repeat
to addToContacts(firstName, lastName, phoneNum)
tell application "Contacts"
set thePerson to ¬
makenewpersonwith properties {first name:firstName, last name:lastName}
makenewphoneat end of thePerson'sphoneswith properties {value:phoneNum}
save
end tell
end addToContacts