to be fair to the LBS if you are not a bike geek (I presume the OP ddn't introduce themselves as such) and rely on the LBS for the repair it probably becomes uneconomic and would be cheaper to buy new pedals
Also if the LBS advise you to do the servicing yourself and you screw it up and fall off then you might blame or even sue them.
__________________
only the dead have seen the end of mass motorized stupidity
Plato
(well if he was alive today he would have written it)