SYRACUSE — National Grid officials Thursday admitted to accidently double billing 5,773 upstate New York customers who paid their electricity bills to the utility online.

Customers who paid their bill online between approximately noon March 7 and noon Monday experienced two debit entries on their bank statements.

“The entries to the customers’ bank statements probably started to appear Tuesday of this week,” stated a National Grid spokesman. “It was a National Grid billing system error, we apologize for the mistake and any inconvenience and confusion it caused our customers. The error is being corrected with a credit to the customers’ bank accounts.”

According to a news release, National Grid will work with the banks of any customers who received a bank service fee because of insufficient funds in accounts that were double billed and attempt to get those fees reimbursed or waived. Double-billed customers will also receive a $25 credit with National Grid.

The company said affected customers are receiving an e-mail alerting them of the mistake and correction.

National Grid encouraged customers with questions to call it at 800-642-4272.