Realwomen.co.nz

It is also complicated by the fact that the business can average your last few Tuesdays or Wednesdays (from memory, over the last month). So it depends when you started working fulltime. You can ring up DOL and just talk to their helpdesk, without bringing the wrath of the business down on you. Unless you make a formal complaint in writing to DOL, they don't take it further. But they will talk with you about it over the phone.
If you look up the site given above, the phone number is listed on that.
Good luck with sorting it so you are happy about the outcome (even if it is just to know that you were fairly paid)..