Hi Jeanne Marie,
Sorry to hear that.
Just in case your store cannot help you out, I want to mention 2 pedals with the polarity switch located outside:
1. The Signal Flex pedal (Model # SF2481)
2. The Satar pedal (Model # VST 125)
Both of these pedals are in the $20 US range.
Hope that you can have this problem solved soon.
Regards,
Sean