WICO faucet handle

[boblovett]

I have a WICO faucet (the only name that appears on the hardware). It is made like a "T" but the upper part of the handle (T) fits over the lower part of the fixture. It is solid on top with no screws or any indication how the upper part connects to the lower. One handle is now loose and somewhat floppy . It still works but I would like to tighten it back up and can see no way to do so.

Any suggestions?