If you sync contacts and calendars through one of your email accounts, go to Settings - Mail, Contacts, Calendars. Tap every account with Contacts and/or Calendar enabled, and turn off the feature. When asked whether or not to delete the events/contacts, select "Delete" or "Remove", depending on the appearing popup.
i sync through an application call "intouchapp" - a very good bit of software -
however i have many duplicates on my iphone-5 so i would like to clear it and sync again -
i have no problems with the contacts on my blackberry torch 9800 or itouchapp contacts -
the contacts in my blackberry are my template