Q: How can I get a report or list of all customers in alphabetical order, to check for duplicates, etc.?
A: Just go to Customers / Find Customers, and uncheck the "Filter by" check box so it shows all customers. If you find duplicates, highlight them (use Ctrl-click to select each one) and use the "Merge Customers" function. Press the F1 key on that dialog to open the Help if you need more details.