I have an Aunt who has the opposite problem with all this. She's elderly, true, but has never married and she gets absolutely hopping mad when anyone calls her anything other than 'Miss'.
I remember a bank clerk once calling her Mrs, and her replying with 'It's Miss...' quite sharply. He then tried Ms, and she hit the roof.
The title didn't exist for her as a young woman, or even as a middle aged one, so she will not deal with it. Nor will any of her friends, or even a lot of my mother's friends. I agree that perhaps it's time women had an independant title, but it's a change that will take time because it's so new a concept that there is a faction of the population, like my Aunt, who regard the title as down-right insulting! To my aunt (and forgive me for this, it's HER opinion, NOT mine!) the title Ms. is synonymous with a 'loose woman'! Until very, very recently, it was a title only for divorced women, and one imported from the states.
That being the case, you can't blame customer services staff for being wary about using it.
The other point here is that, to be truly 'feminist' about names, you would have to take you mother's maiden name, as she would have had to take hers etc.... but then how would that be any different to taking your father's?
The purpose originally of the surname was not to show 'ownership' of the woman and child, but that the woman was happy to state she was married to a man and that she was stating clearly that the child was his. Not so easy to prove back then. The child having the father's name was his ONLY claim to a child. In fact, still, a mother can bar a man from having being idenitified as the father on the birth certificate (unless science proves otherwise)
So many surnames were orginally 'titles' of trade or just literally 'son or daughter of...' that the origins of the naming tradition have been forgotten.
And for real comedy... look up sometime what the word-root origin of 'husband' is. It's very old and has a lot to do with the fact that a man handed over the keys to his money chest to his wofe when he married, and she took his name to claim her right to it!