I see this relates to a Date field issue and not a Phone Number as per your post title.
Your date needs to be in YYYY-MM-DD format - refer http://contactform7.com/date-field/.
The new CF7 date tag is a HTML5 date input type which currently has only limited cross-browser support. See http://www.wufoo.com/html5/types/4-date.html for the low down on this new HTML5 form element.
Jquery Validation For Contact Form 7 is a separate plugin and you would need post any questions about how it works in its support forum.