Sorry this happened to you. Moral of this story -- stay out of that pool store. Pool stores exist to make money selling you things whether you need them or not.

-- Do you have a drops-based test kit? If so, what kind? Post some current numbers.
-- What kind of pool is this and what is the volume?
-- What is the source of your fill water --- a well or city water?
-- What all have you added to the pool, meaning ingredients and not just product names.
-- What size is your pump?