To hear 'Is that Mrs ButtockUp?' Wouldn't bother me at all, I'd just reply 'It's Miss ButtockUp, actually' and then they would apologise and we'd move on.
If Mr ButtockUp had signed up for things and a phone call came through asking to speak to Mr ButtockUp, I'd say either he's here or not.
Often they will say, 'Oh, is that Mrs ButtockUp, then?'
I'd usually say 'yes.'
I get why you might be het up but if I wasn't married, I really couldn't be arsed to launch into a feminist diatribe about titles , societal assumptions, or anything to do with terms of address.
Cold callers don't need blather about 'who do you think I am.'
They're just trying to get through the day, as politely as they can, given that the majority of couples are , actually, married.