what can i do about my acoustic solutions car stereo?

i have an Acoustic Solutions car stereo and when i try to play a cd, it plays ok for thee first two or three tracks but then it switches itself onto the last radio frequency i had on and doesn't recognise it has a cd in the head-set. Then, once it has recognised there's a cd in, i go to play the cd again and it immediately kicks me back to radio. This continues to occur until i eject the cd and re-insert the cd after a few seconds, then it will play the first two or three tracks and kick the radio on again. How can i rectify my problem???