Irate NatWest and RBS customers claim IT problem still not fixed, despite RBS claim that 99% of accounts now up to date

Hundreds of NatWest and Royal Bank of Scotland branches will open with extended hours for a second weekend to tackle the ongoing problems faced by what appears to be a large number of customers.

Ten days after the IT meltdown first left hundreds of thousands of people without access to their accounts, scores of irate NatWest and RBS customers claim they are still missing wages and other payments.

Royal Bank of Scotland continues to maintain it is almost back to normal, with 99% of customers' accounts up to date. Yet the number of customers who have posted on Twitter and contacted the Guardian to say that they are still without money suggests the problems may be more widespread.

Matthew McLeod, a web designer from Nottingham, said: "Last Wednesday my employer paid me as normal but this was not in my account by last Friday, though all my bill payments had gone out.

"I bank with NatWest and so does my boss. On Monday he could see that all his payments had been returned. He printed out a statement and I took this into a branch and they gave me some money.

"Today, the same thing has happened. My boss paid the money out on Wednesday and it hasn't shown up in my account. I am drawing money from my savings account to get by."

Suffolk-based small business owner Daniel Cooper told the Guardian that far from being over, the problems at NatWest appear to have got worse.

"We have money going in daily from our credit card terminal. This money was delayed last Thursday and Friday and arrived later in the day. We have totally lost Monday's money then received funds on Tuesday and Wednesday," he said. "Now their system is not working again and credits made yesterday and Friday have disappeared."

Countless others who face another Friday without a wage payment have taken to Twitter.

"Still no sign of my money as promised by #NatWest‬ This really isn't good enough. Tempted to invoice them for time spent trying to find it," said Rachel.

"Day 9: still £1,200 poorer #Natwest," said Daniel Kitcherside.

"No news on what has happened to my money and why debits have been taken out twice!! " said Barrie DrewittBarlow.

The bank announced on Thursday that it would extend opening hours in branches over the weekend to deal with the ongoing complaints. More than 900 of its branches will be open on Saturday 30 June from 8am to 4pm.

As many as 100,000 customers at Ulster Bank, part of the RBS group, face an even longer wait for their money. RBS has said that these customers will not have access to their money until Monday 2 July at the earliest.

Susan Allen, RBS director of customer services, who appeared on a live web chat on the Guardian Money website earlier this week, told an Ulster Bank customer: "I appreciate your frustration that UB recovery is taking longer than RBS/NW. The problems with UB have been particularly stubborn but we are confident we can fully resolve the issues although unfortunately it will take a few more days."