Out of the Dark (1989)
The phone sex line was for fantasy... now it's for murder!
Ruth is a tough talking owner of a phone-sex operation called "Suite Nothings." Her business venture gets off to a fast start, but the success story stalls when the company's workers start dropping like flies -- each one brutally murdered. The police don't have a clue, and everyone's a suspect, it soon becomes evident that the killer is one of Suite Nothings' most unlikely clients.