Australia’s communications watchdog has taken action against three telcos that allowed over 100,000 spam SMS messages to be sent through its carrier services, including ones impersonating Medicare and Australia Post.

Infobip, Sinch, and Phone Card did not conduct the necessary security checks before allowing the messages to be sent, according to Australian Communications and Media Authority.

Infobip was the worst of the three, allowing 103,146 non-compliant SMSs to be sent.

Sinch allowed 14,291 messages, while Phone Card was issued a warning for not having the necessary systems in place to counter these messages. There was no evidence that this lax security was ever exploited by scammers.

“While there is no suggestion the telcos were involved in scam activity themselves, scammers have used their failures to prey on Australians,” ACMA chair Nerida O’Loughlin said.

“This wouldn’t have happened if the companies had adequate processes in place and complied with the rules.

“Scams that impersonate reputable organisations can be particularly hard for consumers to recognise and there’s no telling how much damage could have been done as a result of these scam texts.”

The ACMA has given Sinch and Infobip “formal directions to comply with obligations.”