Businesses have been left without reliable internet in the industrial area of Tumby Bay, leaving local companies frustrated with the NBN network.
The connection issues were brought to the attention of local council in November 2018, when the council depot on Pumpa street experienced issues.
Reliable speeds can depend on the distance to the nearest node.
Ricky Trenberth, operations manager at Curtis's Sales and Service, which is located in the industrial area, said the issue had been ongoing for six months.
He said while they were within 800 metres of the node as the crow flies, the cabling was much longer.
"It stretches 1.3 kilometres before it reaches our premises, which is nearly twice the distance," he said.
"Down at the silos, they may as well be in a different postcode.
"I would wager that everywhere between here up to Whyalla along the coast would be in the same boat."
Mr Trenberth said some areas were worse affected in the mandatory disconnection areas, but slow connections had still affected business operations.
"Speeds are 17 or 16 megabytes per second on a good day," he said.
He said NBN speeds were meant to be 40 to 50 megabytes per second.
"You can't run a business like this," he said.
"We've got staff in different stores that need remote access to our systems, and if the connection drops out they can lose their work and have to start again...it drives us absolutely mad."
He said Curtis's internet service provider had allowed them to be released from the contract, as speeds were slower than paid for.
"We'd been paying for speeds three times more than what we were getting," he said.
"But where's the alternative when all providers can only provide the same thing?"
Planning has commenced for the installation of an additional micro-node to improve service to the area, but the NBN have yet to put a timeline on the fix.
Tumby Bay mayor Sam Telfer said the issues needed to be rectified as soon as possible.
"There needs to be a clear understanding from NBN Ltd of the expectations and needs of business and community," he said.
"What has currently been delivered seems to be insufficient."
An NBN spokesperson said the distance of some businesses and homes meant additional work was needed.
"NBN will build and install a micronode on John St, Tumby Bay, in the second half of 2019, which will allow additional premises in the vicinity to connect to the nbn fixed line network," they said.
"It will also improve speeds and connectivity for premises already on the network in the industrial precinct in the north-west part of the town.
"Residents and businesses experiencing any issues with their existing service should contact their phone or internet provider."