Beware - Citi Cash Returns Card Charges Hefty Over The Credit Limit Fees

A couple of months ago we had opened a Citi Cash Returns Master Card account to avail it's promotional rate of 5% cash back on all purchases for first 3 months. At present the effective cash back on this card is 1.20% on all purchases for the first year.

Well, to maximize our rewards we were using this card for all purchases, big or small. And on that spree, while booking a flight to London, we