A local power loss and hardware failure at third-party vendor FIS appears to be at the root of a several-day service interruption that saw thousands of Capital One customers unable to access their direct-deposited paychecks, see their account balances or log in online.

Jacksonville, Florida-based FIS, in a statement Monday, confirmed the “system outage,” which began Wednesday, adding that it was not the result of any cyber incident and that affected clients “are back to processing business as usual.”

Tulsa-based Bank of Oklahoma counted itself among more than two dozen banks affected by the outage, CBS News reported.

“Our digital platforms are back online, and balances should be displayed correctly,” the bank wrote Friday in a statement on its website. “We will refund fees incorrectly assessed on accounts impacted by the outage.”

Of the banks affected, Capital One took the brunt of online complaints.

“What’s in your wallet?” one user posted on X, formerly Twitter, in a play on the company’s slogan. “Nothing if you bank with Capital One.”

Some customers were decidedly less cheeky.

“My money hasn’t come through since Wednesday!” another user wrote. “I have to pay my [expletive] mortgage! I have to pay for gasoline! I have to feed my children! I called and was hung up on after inputting all my information! Something is very wrong!”

Capital One posted Sunday that “account functionality for all customers is now restored.”

“We sincerely apologize for how frustrating this experience has been,” the bank added. “We are committed to making it right. We encourage customers to check their accounts online and contact us for any support.”

Nearly 4,000 Capital One customers had reported issues to the website Downdetector between 9 a.m. Thursday and 9 a.m. Friday. That number fluctuated Friday but rose to around 4,000 again by afternoon.

"We are working around the clock with our service provider to resolve this issue,” Capital One wrote in response to one X user Friday. “Systems are gradually updating and when systems are restored, you will be able to see your expected transactions online."

The bank at the time characterized the issue as “temporary,” but customers fired back that they had been waiting three days.

The outage comes at a tenuous time for Capital One, which is trying to present itself to regulators as a worthy acquirer of the credit-card network Discover. The bank’s shareholders are set to meet next month to vote on the acquisition, which has received a green light from Delaware’s financial regulator. The companies have said they expect the transaction will close by March.

In another potential blow, though, the Consumer Financial Protection Bureau last week sued Capital One, alleging the bank “cheat[ed] millions of consumers out of more than $2 billion in interest” by failing to tell them of a higher-yielding savings account product.

Capital One is not the only top-10 U.S. bank to have experienced service disruptions last week. Hundreds of Citi users reported issues to Downdetector, although it’s unknown whether that outage is connected to Capital One’s or BOK’s.

Some Citi customers posted on X that they had received fraud alerts, experienced long hold times with the bank's fraud department or couldn't access their mobile accounts.

A Citi spokesperson cited “technical issues with [the bank’s] mobile app experience, which we are working quickly to resolve.”

"We are currently working on this and ask that you try calling in another 1-2 hours," a Citi representative, responding to complaints on social media Wednesday, wrote on X.

Several Capital One customers, during the outage, appealed to the bank over basic needs.

"It'd be nice to get paid. I'm hungry," one user posted on X. 

“I was supposed to get paid yesterday, and it's still not here," another user wrote. "Guess I'll be eating ramen again tonight."

Others pointed to Capital One’s lack of a time frame to settle the issues.

"This is now Day 3, and my paycheck is still not deposited or showing as pending in my account,” one person said Friday. “I would appreciate an update on the ETA for a resolution."

Mike Matsos, a Birmingham, Alabama-based hospitality worker, said that as of Saturday morning, Capital One still had not processed his paycheck, which he was expecting Thursday. The delay forced Matsos to take money from his savings account to buy groceries, he told The New York Times.

“If they don’t get it to us in the next few days, I won’t have any savings left to pull from and I won’t be able to pay any bills,” Matsos said. Matsos received access to his paycheck later Saturday, he told the Times.