Telstra's AFL Live Pass app has been described online as a "rip-off", "a joke" and "useless".
Football fans have long reported various issues with the app, which allows subscribers to stream AFL matches live on mobile and tablet devices.
The Australian Competition and Consumer Commission (ACCC) is alerting subscribers they may be entitled to a refund, after Telstra introduced a screen-size restriction meaning games could not be viewed on a full screen on many devices during the 2017 season.
On January 31, Telstra introduced a screen-size restriction of seven inches (17.5 centimetres) diagonally - the size of an iPhone.
The change means there is a sizeable black border surrounding the live-stream when they watch on devices such as the iPad, with matches only becoming available in full-screen mode 12 hours after the end.
Many fans were angry when they discovered the sudden change as they watched the Collingwood-Essendon practice match in February.
The ACCC said the Live Pass app was still advertised on the AFL website with images of matches appearing full-screen on tablets, with the tagline "Watch every AFL match live on mobile and tablet".
"The ACCC was concerned that footy fans may have subscribed or renewed subscriptions to the AFL Live Pass thinking that they could continue watching live AFL matches in full-screen on a tablet, when this was not the case," ACCC chairman Rod Sims said in the statement.
"Some footy fans were locked into a Telstra subscription before the screen size restriction took effect.
"When businesses make changes to the subscription terms of goods or services, customers should be clearly notified of the change so people are able to make an informed decision about whether to continue their subscription."
Telstra has been offering refunds to annual AFL Live Pass subscribers, and those who downloaded the app on a tablet before January 31, via its Crowd Support page since August.
The refund form will be available until March 22 next year.
A short statement on Telstra's website said: "As part of Telstra's digital rights agreement with the AFL, the 2017 Season live match image on the Official Live App was reduced from a maximum of 11 inches to 7 inches diagonally."
Many subscribers have reported issues with the app on Telstra's Facebook page, including problems with logging on and using the app on a variety of devices.
