The Central Texas Regional Mobility Authority (CTRMA) said on Wednesday that a glitch in its system has caused over a thousand Texas drivers to be overcharged.

Despite paying their bills on time, about 1,200 TxTag and CTRMA customers were charged late fees after they used transponders to pay their tolls, resulting in high toll bills.

“Our vendor alerted us on November 9, 2022, to an issue that delayed the posting of certain payments,” CTRMA said in a statement to Fox News. “This issue impacted a very small subset of the payments processed between October 21 and November 14, 2022.”

TxTag drivers were charged with inaccurate bills on toll roads 183A, 290, 71, and the Mopac express lanes that cut through Austin, reported Fox News.

The total amount of overcharges was not disclosed, but unpaid bills can result in as much as $25 in late fees.

Officials say they are working with the vendors and their payment processing company to find a solution and fix the system glitch.

All incorrect charges have already been reversed, said the agency, but refunds for drivers who already paid their fees are still processing. Refunds may take a couple of weeks to process, reportedly.

The money will be sent by mail once the refunds are processed. Online accounts can be checked at mobilityauthority.com to ensure that the charge was reversed and all payments are settled accordingly.

In the coming week, customers should expect to receive letters explaining the situation.

The Texas Department of Transportation’s tolling system has faced billing problems with customers before, such as in 2015 when the agency had to repay about $1.7 million to tollway users after the users were overcharged.

In August, KHOU reported another case of incorrect TxTag billing. In that case, drivers were incorrectly billed as a result of the license plate reading system interpreting the letters “I” and “O” as the numbers “1” and “0,” respectively.

In August 2021, TxTag also overcharged customers and added late fees after customers received their bills late.

It is currently unclear how much money the state will owe drivers involved in this recent debacle or when TxTag will succeed in sorting its billing issues conclusively.