Woolworths Store Card

Woolworths keep on blocking my store card for no reason at all. No installment due. Card paid up to date, but every time I want to purchase on my card, IT'S BLOCKED YET AGAIN!! This happened at least 4 times already, Very frustrating!! Why give a customer a store card if you block it every now and then, then it's long conversations on the phone to get it unblocked again!! Very disappointed