It is up to the parties. If a subcontract is involved Mediation keeps you in control of the outcome . Mediation can help equalize power imbalances. If so, mediation will help you rebuild a good working relationship or sever business ties with the best outcome possible for everyone involved. Mediation can help equalize power imbalance.
Mediation works regardless of a company's written policy.
Mediation keeps you in control of the outcome and is a low cost solution to reaching a solution so that the problem does not escalate any further. Less conflict means your workplace is more productive and pleasant. Better communication means a more efficient and effective workplace.