SaskTel, the provincial Crown corporation that provides telephone and communications services, says a system glitch has resulted in some 9,000 customers being billed incorrectly, from a few cents to as much as $100,000.
The company said the errors took place during network enhancements and affects wireless customers.
The mistakes appeared on bills generated in November where customers were billed for data use using the wrong rate.
The company said credits will appear on statements to fix the mistakes.
As well, customers will be notified by text messages and by phone. Letters will also be sent out.
"SaskTel will be asking those customers that are impacted to not pay their November bill," the company said in a statement Tuesday. "The appropriate credit will be applied on their December bill and there will be no late payment charges."
SaskTel said it will also make sure automatic bank withdrawals do not take place on affected accounts.
"We are very aware that customers are sensitive about things like this," Michelle Englot, a spokeswoman for SaskTel, told CBC News Tuesday. "That is one of the reasons we decided that we definitely needed to contact any customers impacted by phone, personally."
According to Englot, about 25 customers were mistakenly billed over $10,000, with a handful of those receiving incorrect bills for $100,000.