A NORTH Toowoomba NBN customer has experienced the same woeful internet connection that has threatened to cripple a family-owned business.

The resident, who declined to be named, signed on to the new fibre optic system when it was first installed in his suburb about a year ago and enjoyed a faster connection for a few months.

But as more customers signed on, his internet speeds began to slow to the point where the service drops out completely.

"We were fairly early adopters, but it has been getting gradually slower as more people come on to the NBN," he said.

"More data is being used and there's not quite enough infrastructure to go around for everybody."

He received a fault notice from his internet service provider iinet on October 14 which explained the "slower than expected speeds, increased latency and packet loss during peak hours" was being caused by "backhaul links to Toowoomba exchange have reached capacity".

The notice from iinet said it was working with its network partner to increase capacity, but could not give an estimated completion date.

During a call to The Chronicle, the resident's VOIP phone dropped out which he said was typical of the connection.

"Sometimes you don't even know when you have lost it (the phone) and we are restarting the gear four or five times a day," he said.

"We get a 250GB a month allowance and we generally wind up using close to that."

He said more people were taking the opportunity to get faster internet, but it was causing delays on the network.

The iinet notice said engineers had been working to increase the capacity of the affected links.

An NBN spokeswoman said the slower speeds were the responsibility of iinet, not the NBN.

Meanwhile, Toowoomba First Aid Supplies owner Katie Ley said connection had been restored at the business.

"We were notified by email that the services had been restored," Mrs Ley said.

"Now business can go ahead with our receptionist getting straight onto email and getting on to everybody."

Mrs Ley said she was working with Telstra to organise compensation after almost five months without internet.

The spokeswoman for the NBN confirmed investigations into the cause of faulty internet speeds at the Toowoomba First Aid Supplies had been resolved.

She said the fault was detected in the customer premises equipment which a Telstra technician had repaired.