A family of Microsoft word processing software products for creating web, email, and print documents.
The data duplications are likely to be the result of inserting the mergefields multiple times.
The mergefield \b & \f switches don't work with other switches. Presumably you have conditional content to go with the # (e.g. 'Phone:'). In that case you could use a field coded along the lines of:
{IF{MERGEFIELD Phone}<> "" "Phone: {MERGEFIELD Phone # "'('###') '###'-'####"}"}
Note: The field brace pairs (i.e. '{ }') for the above example are all created in the document itself, via Ctrl-F9 (Cmd-F9 on a Mac); you can't simply type them or copy & paste them from this message. Nor is it practical to add them via any of the standard Word dialogues. The spaces represented in the field construction are all required.