Does the marriage contract take effect if a woman appoints her employer to marry her off (she being of sound mind and 24 years old), and then offer and acceptance take place between the husband and wife, in the presence of the employer as guardian and two sane, adult, upright, competent, and religious witnesses? And is it permissible for the woman, after this offer and acceptance from both parties, to marry another man without the first one divorcing her?

The marriage of a woman without a guardian (wali) is invalid according to the majority of scholars. What the employer did by marrying this woman to you is a corrupt contract, and therefore you both must repent.

A woman marrying another man before she is divorced from you is impermissible according to most scholars. This is because, despite the invalidity of a marriage without a guardian, jurists have differed on whether such disputed marriages require annulment or divorce. Therefore, the matter must be referred to a Sharia (definition) court for a ruling.

Regarding seeking religious verdicts (istifta'), it is permissible for common people to follow a specific madhhab (definition) (school of thought) or to ask someone whose knowledge they trust, without following whims or seeking out concessions.