Theoretically the could choose a different agency, but that would even further delay and cost them, as the satellite will at least need moved to the new launch centre, and probably de-mounted from the Briz-M, shipped, and mounted to the alternate launch platform . Plus a rocket, fuel, and a launch slot will need made available. My bet is they have launches scheduled years in advance, and it would cost quite a lot to bump a launch for an "emergency" commercial launch.
Practically, changing launch agencies won't happen. It will be easier and cheaper to ride out the issues.