Brakes problem
2006 Nissan Murano 6 cyl Front Wheel Drive Automatic 55000 miles

i have a 2006 nissan murano they just replace the front breaks due to a cracking sound on the breaks. 3 days later i still have the same noise the sound comes from the back breas what can it be. this happen at nay time of the day any speed or any gear, going forward reverse. any answer please
thank you