Talk about bill shock.

Saskatchewan Telecommunications Holding Corp. is blaming a technology glitch for a billing error that slapped some wireless customers with incorrect charges as high as $100,000.

The provincially owned telco, more commonly known as SaskTel, said roughly 9,000 of its more than 600,000 wireless customers were affected by the billing mistake, which occurred late last month.

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"As part of the 4G LTE (fourth generation, long-term evolution) network capacity enhancements, SaskTel was installing new network hardware and a recent systems upgrade caused a billing error," the company said in a statement on its website.

"Affected customers will receive a bill that may incorrectly rate their Saskatchewan data at U.S. data rates. The charges may range from a few cents to $100,000."

SaskTel gave assurances that affected customers would not be expected to pay their November wireless bills, adding late charges and interest fees would not apply in those cases. The telco plans to issue automatic credits to affected customers on their December bills.

"You'll receive a phone call and a letter from SaskTel with more information. If you don't receive a phone call or letter from SaskTel, you're not impacted by this error and your bill is correct," the company said.

"We apologize for any inconvenience. Thank you for your patience as we continue making network improvements."

Spokeswoman Michelle Englot said this is the first time that SaskTel has experienced such a billing error. "The error was flagged when we noticed high U.S. data roaming charges," she said in an e-mail.

This isn't the first time, though, that SaskTel has had a high-profile problem with its 4G wireless network. In fact, its network expansion has previously faced a barrage of criticism for spotty coverage and congestion as more of its customers upgrade to data-hungry smartphones.

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Premier Brad Wall has been among those critics. He has previously complained about dropped calls on SaskTel's network, first on Twitter in late 2011 and then in a Speech from the Throne.