Fight tooth and nail to get UPS to cover the cost of replacing the amp. If that does not work, you could also remove the amp and take it to an electronics repair shop. Stress the fact that the technician find an exact matching replacement part if possible, even if it costs you more. As a last resort, you can try to have Axiom give you the replacement part number for the potentiometer and buy one online and change it yourself.

Behringer 1030A, SVS PB-12 Ultra, Etymotic ER-6i
PS3, SGT 10.1, Sansa Clip
Auralex