Many Spark users nationwide are reporting they are not able to make or receive calls today as the company faces major technical issues.
Some customers posted to social media this afternoon saying the issue has been ongoing since last night.
In a post on Facebook, the phone company said they are aware of the issue and are urgently working to identify the cause.
It explained customers could still make calls over Wi-Fi and data using apps such as WhatsApp, and that texts could still be sent and received.