Troy, unfortunately every Jaycar store has recently had their POS system "Upgraded" (

) so you
must have the receipt for a refund or warranty repair... the 'puter will just flat out refuse to allow it otherwise.
For an exchange you might be ok, depending on who serves you, you might get a straight swap.
Don't tell them you measured voltage with the lead in the amps socket

It honestly wouldn't surprise me if you got a bad one... I have had customers exchange a couple for various reasons. (most recent had a backlight that wouldn't turn off)
Don't let that discourage you though, in the last year we've had 4 maybe 5 meters returned.