The last suit I filed against a telemarketer was against the “beneficiary” company as the lead generator who called me was of course overseas. They claimed that they could not be held vicariously liable for the calls but ultimately settled with me because litigating that would cost a lot more money than the settlement amount.
Some state statutes go further than the tcpa and address vicarious liability specifically, so if you’re in one of those states you have a stronger legal leg to stand on.