Australian telco Telstra tried to make amends with its customers on Sunday night, offering 24 hours of free mobile data to make up for four outages over the past two months.

During its Free Data Day, which started on Apr. 3 at midnight, Telstra customers downloaded 2,686 terabytes of data, equivalent to 3.4 million HD movies. But the amount overloaded its network and customers complained of slow download speeds and blocked usage, according to a report by news.com.au.

Telstra said the bottlenecks were isolated, and that the “majority of customers continued to experience a reliable level of service.” A Telstra spokesperson said that periods of slower speeds may have been caused by “pockets of high demand in some areas…if a large number of customers are in a single area.”

Some customers suggested the company was throttling the network, preventing users from accessing truly unlimited data. Telstra explained to CNET that “traffic balancing mechanisms” were put in place; the software adjusts throughput at a group level. 

“Arguably they throttled themselves,” Telstra told CNET. “They shared the bandwidth that was available, and it meant that they all slowed down when they all tried to use it at once.”

Customers downloaded 46 percent more than the amount downloaded on the company’s first free data day in February, according to Telstra. The day of free data cost the company millions of dollars. 

So what can other service providers learn from this? In order to win your customers’ trust back after an outage, you need to make sure that whatever you have decided to do to support this is realistic and that you can deliver successfully on your promise. 

Even if you’ve never dealt with an outage before, you should have a comprehensive plan to communicate with your customers in place so you know exactly what to do should one occur. PagerDuty has a helpful list of best practices to communicate an outage with your customers.