BOQ eftpos declined 51

Received $50 card as a birthday present. Tried to buy a top from an online website (according to the price I would've had $10 still on it after purchase), using the credit card details - declined. Set up a paypal to try it that way, had to verify it ($2 deduction) and wait for a month to receive the card statement as you can't view this online, but since I should've had enough money on the card still, I tried buying it through paypal - declined. I decided to check my balance on the card and alas, instead of having $50, there was only $36 on the card, thus I couldn't buy the top and missed the special edition :(. Such a scam, do NOT buy.