The VMS systems is fairly limited in the respect that there is no calibration procedures, as far as I know.
You should double check the wiring, since it's not likely that both transducers failed at the same time, but stranger things have happened. Be sure to check all connections, DPU, any bulkhead fittings and terminals. Also look for butt splices in the bundles.
Then reach out and try to get replacement transducers.