Toilets, Sinks, Showers, Tubs and Disposals - tub cold water fixture woren out???

Hi I have a three fixture set up in my tub. I have been in this house for 2 years. Since the beginning the cold water fixture required a great deal of effort to complete turn off. From time to time the handle (standard handle attached to a long maybe 3/16" wide stem with a gear-like end) would pop out but I was able to work it back in and it would stay for a while. It has finally popped out for good. I am unable to get it worked back in so I am not able to turn on or off the cold water and now when I turn on the hot water the cold water handle that I have just inserted into the pipe for now shoot across the tub -- hot water flows from the cold water pipe?:confused:

I'm not exactly sure what fixture this is but it does sound like a issue with guts. Go buy new ones at a hardware store. You can remove the old ones(turn off the water first!) and bring them with you to compare.