The biggest issue was people rushing to take advantage of the offer by downloading as many movies and television series as they could.
Telecom ran the promotion, for all customers on the pre-paid and post paid network, from 7pm Thursday to midnight Sunday, as part of its 23rd birthday celebrations.
Chief technology officer Rob McFadzien said demand was much higher than expected, with traffic volumes swelling to between four and ten times normal levels.
He said up to five times more subscribers than usual were using data over the long weekend, affecting speeds and causing drop-offs in certain areas at times.
Frustrated members of the public were quick to start venting over the phone and online, complaining about difficulties accessing the free data.
McFadzien said Telecom’s technicians identified system issues and worked with teams in New Zealand and China to take action.
He admitted the offer “backfired a bit” because of the congestion but said Telecom “learnt a lot over the weekend”.
“To us it’s positive. We know there’s a lot of demand out there that is held back. People aren’t using their phones as much as they could.”
The offer showed many people want to use 3G – which Telecom launched in March - but are choosing not to because of the price, he said.
McFadzien said the biggest cause of problems was the sheer number of people trying to download movies and television series, which uses huge amounts of data.
Acting chief executive Helen Aoina said the overwhelming response showed a definite shift towards Cook Islanders wanting to take up the mobile internet service.
“Obviously, anything free is going to have a far greater use. It’s a good indication that pricing is a factor in stopping people using what’s available.”
She said that although Telecom has no immediate plans to drop its 3G prices, the weekend’s learnings will certainly be used to influence future pricing decisions.
McFadzien said the company will not be upgrading its network in response to last weekend because normal traffic levels are perfectly manageable.
But he said the promotion did provide information about how to improve the network in the future.