Strong Metallic Taste/odor after carbon professionally replaced.

[rosielp]

We had our whole house Culligan Gold Series Automatic Water Conditioning system serviced 1 week ago. They called to say it was "time". It had been 5 years since the previous homeowners had the carbon replaced. We are on a well but we were having NO PROBLEMS AT ALL with our water taste or odor. The salt level was low in the tank but not near empty. While working on it, he suggested a reverse osmosis system, but having no problem at all, why would we? He replaced the carbon and filled the salt tank with their brand of salt. About 2 days later, the water became terribly metallic smelling and tasting . It also leaves a sort of stinging feeling on our tongue that doesn't go away. It's scary. They suggested recycling the carbon tank that maybe iron was "knocked lose". We did a few extra times. No change. They came and dumped a large container of Iron Out into the carbon tank? Im not sure of where the Iron Out went. He recycled the system completely. Now it's worse! What could have gone wrong here? They are the professionals, right? Please help!