Car Wireless Fm Transmitter HOW COME MY MONSTER ICARPLAY WIRELESS PLUS CAR STEREO FM TRANSMITTER/CHARGER CAN'T USE OTHER CHANNELS?!!!!!!!!?

HOW COME MY MONSTER ICARPLAY WIRELESS PLUS CAR STEREO FM TRANSMITTER/CHARGER CAN'T USE OTHER CHANNELS?!!!!!!!!? - car wireless fm transmitter

I have not tried to work differently, but I was the first record I was working, but I tried to use other options do not work, why? I do not have all steps to change the channels and still work. PLEASE HELP