A New Zealand businessman was shocked to find $23,000 in phone bill charges after an international phone hacking scam targeted his business lines.

The hackers racked up the massive bill in only two days, according to 3 News. International hackers often use automated dialing software to call thousands of phone lines per minute until they discover a PABX phone with an unsecured voicemail port. Companies commonly use PABX phones to handle calls, as well as to transfer callers to its directory.

Once gaining access through the voicemail, the hackers begin routing their customers' calls through that number for a few days. Then they move on to a new victim.

In this case, the victim was initially told he'd have to pay about $6,000 toward his bill, but following the news story, he was released from any fees.