faint ringing noise after brake service

[Lukey75]

Hi,i got new front/rear disc rotors and brake pads put in the other day.
Since then when ever i drive i hear a faint ringing noise like a cats bell,soon as i apply the brakes the noise is gone then starts up again upon accelerating. would anyone know why? thought id ask here before taking it back to the auto shop. thanks in advance.

[wildss]

didyou bed them in properly?