To accept or decline a contact invitation, click on the Inbox Tab. Under the request select Accept Contact Request or Reject Contact Request. Don't worry, this person won't receive a message if you reject the invitation.

Here's what happens: When an invitation is sent to you, your name on YogaTag will have a  have requested this contact note underneath it. If you accept the invitation, this note will disappear. If you decline, the person won't receive any notification from YogaTag.