Stop time travelling?

Heh, no seriously that's a bad issue.
There's not much you can do except for contact them.

In fact, my recommendation is to contact them daily.
This will annoy them, harrass them, and clarify that you are serious.
It should drive them to insanity to actually figure it out.

Otherwise, if you stay quite, it might get sweeped under the rug as these things are prone to do.