If you're about to use your Visa card to pay for something in Europe, you may want to use cash instead.<p>Visa announced Friday that it's experiencing a "service disruption" that is preventing transactions from going through. Right now, it seems like these problems are localized to the UK, Ireland and parts of Europe. Visa says it's aware of the problem and developing a fix, which might be working already. Major UK bank HSBC claims that service is slowly returning.