Good heavens, that's terrible! Was it through the hospital, or a private company?
When I had my 19wk scan last time the u/sonographer was a right cow too, she practically ignored DH - had her back to him and told him to just watch the screen. Then she just talked to me, basically. And told us the same about the sex - "You should have told me earlier." Well we've never done this before, how are we supposed to know?!?
Really sorry that you had a crappy experience. Don't blame you for feeling ripped off. BTW, if it is a private clinic, I'd be requesting another one as the technician sounds like she was below par - I've never heard of them having to do an internal at 20 weeks either!