Re: Mam or ms?
I wouldn't use a salutation of any kind to someone whose name I didn't know. I work part-time in a shop and I would never call a customer "Madam". It sounds very old-fashioned, far too formal and it suggests a woman of a certain age.
If someone dropped something in the street, I would shout "Excuse me" or maybe even "Scuse me love!" Most women don't mind being called "love" in the UK, as long as the person saying it is also female. Some don't mind men using it but I wouldn't recommend using it to someone you don't know.
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.