Carriers have been slow to address the growing robocall problem, but the Federal Communications Commission may be about to force their hand. In a letter to fourteen US carriers, FCC Commissioner Geoffrey Starks today called out the confusing and often ineffective options available to consumers for fighting automated spam calls, and threatened regulatory action if the carriers do not improve.

“Despite historically clamoring for new tools, it does not appear that all providers have acted with haste to deploy opt-out robocall blocking services,” Starks told the carriers. “The Commission spoke clearly: we expect opt-out call blocking services to be offered to consumers for free. Reviewing the substance of these responses, by and large, carriers’ plans for these services are far from clear.”

In June, the FCC voted to allow carriers to block robocalls by default, and pushed carriers to adopt protections using the STIR/SHAKEN protocol before the end of the year. In response to that order, Commissioner Starks asked telecoms to inform the Commission of their plans to offer free robocall-blocking services by default.

But the responses to that request, published today alongside Starks’ letter, show a range of confusing and obscure tools. AT&T released its own default robocall-blocking system (dubbed “Call Protect”) on July 9th, making it the default setting for all newly installed lines. T-Mobile’s default “Scam ID” system attempts to identify robocalls, but users must opt into the more comprehensive “Scam Block” service. (Both products are free.) Comcast took a similar line, telling Starks that it offers “a range of free robocall mitigation tools that its customers may opt in to using,” although it’s unclear which of those tools will take advantage of the FCC’s new mandate to proactively block robocalls.

Other providers are still working on their robocall services. Verizon offers a “Call Filter” service based on STIR/SHAKEN, but told the Commission that it was “actively working on ways to ... more broadly make call blocking available to our customers.” (The company offered no timeline for that work.) Sprint said it would offer a free call-blocking application “in the near future.”

Many carriers also boasted blocking millions or even billions of robocalls a year with their current systems. Still, those efforts don’t seem to be slowing the spread of the calls, which have reached epidemic proportions. In January, a survey from YouMail estimated that nearly 48 billion robocalls were made in the US in 2018, an increase of more than 50 percent from the previous year.

The carriers’ answers don’t seem to have satisfied Starks, who hinted at potential regulatory action if carriers aren’t able to swiftly deploy new tools. “If we find that carriers are acting contrary to our expectations, we will commence a rule-making,” Starks wrote. “I expect to be updated by carriers as progress is made on offering free call blocking services and recommend that carriers not stop until the job is finished. The sooner, the better.”