Tyro, the largest provider outside the big four banks, has had problems with its terminals, leaving 19 per cent of its businesses unable to process payments for more than a week.
Among those is local drive-through coffee shop Busy Bean, with both its Shepparton and Moama locations having to turn customers without cash away in droves.
Owner Dylan Butler said his business had been decimated by the outage.
“We're on day eight without EFTPOS now, it's been a nightmare,” he said.
“Turnover has had a 30 to 40 per cent reduction, it's been disastrous.”
Like many of Tyro's customers, Mr Butler said the outlet's response had been slow and vague, with little information relating to a timeline of when normal service could resume.
“We've had generic emails explaining the situation; it seemed to take them a long time to even work out what had happened, which was strange in itself,” he said.
“The latest is our terminals have been picked up and will be re-dispatched. They were picked up today and they're telling us two to four business days. We're not sure, but we're just hoping it's two.
“In the past when EFTPOS has gone down, the worst it's been is for 30 minutes, an hour — never in your wildest dreams could it be down for eight or nine days.”
In a statement to customers, Tyro said it would begin working through potential compensation once the issue was sorted.
“We want you to know that we will not stop until we have completely resolved this issue, at which point we will turn our attention to how we will make amends for this disruption, which is another frequently asked question,” it read.
“Please know that all options are on the table and once we have completely resolved this issue for all our customers, we will be proactive in progressing these discussions.
“We apologise again for the disruption and frustration this has caused.”
Mr Butler said anything short of "significant compensation" would leave businesses turning away from Tyro.
He added the Moama store had copped a "double-whammy", with the EFTPOS outages and border closure obliterating what is usually its second-busiest week of the year.