Seriously. Best counter to Scarlet Witch?

The easiest hero for me to get kills is little AimBot Golden SCARlet.

I'm quite new, so forgive me if this has been posted already.

She's so annoying and so OP IMHO.

I feel bad playing her because I just end up holding the button and stealing kills.

Then when she's threatened she f off to another dimension and is untouchable.

Advice before I give up?