Defendant waived its right to compel arbitration by participating in a putative class action for 24 months after service before moving to compel arbitration.  It could not excuse the delay on its belated discovery of the arbitration agreement bearing plaintiff’s signature sisnce it alleged arbitration as an affirmative defense in its answer, knew that when plaintiff was hired its policy was to require new employees to sign an agreement to arbitrate, and knew the terms of the standard form arbitration agreement it used at that time.  By participating in the plaintiff’s class action discovery during the  24-month delay, defendant took actions that were inconsistent with its right to individual arbitration, and by doing so it prejudiced plaintiff since he lost the advantages of swift inexpensive arbitration by pursuing classwide discovery and relief in the meanwhile.