Create a Drop down that will list all names starting with initial letter of names.

I have a long customer listing, names 5 to 36 characters and several with their location in the name as well as a few common duplicate names. I am trying to produce sheet where the customers name once selected opens in the customers spreadsheet and data can be added/amended for sales etc.The lists are not in alphabetical order as when created a customer number is automatically allocated. My aim is just to type in the first letter of the name and the dropdown appears the customer is selected and their card appears.
I have tried data validation, lookup, vlookup, Dropdown and Match/find. they only return the first record found and no sign of any others. Find returned all instances of the letter appearing in every name. Can anyone advise which way next to try or am I on to a hiding to nothing. Thanks for any comments and help.
Mike.