We had some switches similar to what you are describing. I found these to be well made and easily repaired if they are just pushed in too hard and lose their contact ability. You can take them apart carefully and bend the copper contacts back so they make a better contact and clean the surface with some emery paper. If the actual rocker broke, that may be a different issue. Has anyone posted a photo of these switches?
I have two low voltage transformers, one in the basement, and one in the gargage. My house was built at the end the 50's. I am assuming the equipment is that old. I have been having trouble with one of the transformers. Are transformers still manufactured, and can I purchase a replacement? Are the Rocker Switches still available too?