I used one of my credit cards that I rarely use last week and got the Pin wrong. I eventually found the correct PIN but I called the company to ensure that I hadn't blocked the card. They offered me 9 months interest free credit which was very useful as I have a few big purchases to make and I have just changed from a weekly paid to a monthly paid job. I assume that I only have to make the minimum monthly repayment the clear the balance before the interest free period ends to benefit from this offer.
Kevin