Did you read my last post? You cannot just go to a shop and take their word anymore - most of these shops will take advantage of you given the chance, which is likely what happened here.
Before you agreed to change rotors and pads, did you ask them to show you the issue, and explain how it would cause the noise? It would have been as simple as walking you into the shop to show you while the car is on the lift. Are you sure that they changed the rotors and pads? What good is the 1 year warranty if they didn't even fix the problem?
They basically sold you parts and service you probably didn't need. You can either go back and demand that they fix the problem at no further cost to you, or refund you for the money you spent, because they did not diagnose your vehicle correctly or fix the problem. You may have to resort to threatening to leave a complaint with management, leaving a negative review on Google, Yelp, etc., and going to the media. Shops run these scams because they know most people are too lazy, or too embarrassed about being taken advantage of. They know most customers will not take further action.
If you're interested in fixing the problem, find a different, reputable shop, and ask them to diagnose the issue. Make sure you request that they show you exactly what is causing the noise and how they plan to fix it. Establish what happens if you pay for the repair and the issue remains.