WASHINGTON — The Minneapolis Veterans Affairs' faulty inpatient billing system has resulted in some Minnesota veterans having to pay thousands of dollars more in co-pays in the last five years.

In a letter sent Thursday to the Secretary of Veterans Affairs Robert McDonald, all ten federal Minnesota lawmakers questioned how the potential for veterans to pay more in copays will affect them and what the VA plans to do to help.

The letter pressed McDonald to address what authority the VA has to hold veterans accountable for these unbilled services and how many veterans will be billed. The letter also questions whether similar errors were made in outpatient billing and where the collected money will go.

The lawmakers also inquired what services will be in place to help veterans through this process and whether there will be a grace period provided.

In a rare instance for Capitol Hill, the letter was signed by all 10 of Minnesota's congressional members and four of their neighbors from Wisconsin.

"Our veterans sought care at the Veterans Affairs Medical Center in good faith and should not be suddenly saddled with thousands of dollars in bills years later due to the VA's inability to properly track, record and bill for services," the lawmakers wrote. "Each year, Congress appropriates billions to the VA for administering medical care and benefits earned by our veterans through their service to our nation."

The lawmakers urged the VA to investigate how the charges went unbilled initially and said the issues need to be corrected for the future.

The co-pays oversight is the latest in a string of black marks against the VA in Minnesota and Wisconsin. Last November Minnesota lawmakers sought answers from the Hibbing VA that supposedly tampered with patient schedules and in October sent a letter regarding Minneapolis VA employees falsifying records.