A word to describe a person who doesn't use their own products or policies

Solution 1:

Some would call the person a pragmatist:

One who acts in a practical or straightforward manner; one who is pragmatic; one who values practicality or pragmatism.
One who acts in response to particular situations rather than upon abstract ideals; one who is willing to ignore their ideals to accomplish goals.

Others might term him or her a ditherer, or might apply previously-suggested terms turncoat or renegade, although I think related words apostate, one who has lost the faith, or defector, with its sense of disloyalty, are more appropriate. Also consider phrases like “strayed from the fold”.

Heretic also is relevant. From en.wiktionary, heretic means “Someone who, in the opinion of others, believes contrary to the fundamental tenets of a religion he claims to belong to”, so one may say, figuratively, that an employee who for some reason prefers the services of a competing company is guilty of heresy, or is a heretic.