The owner of a local internet sales business has been left angry and frustrated by technical woes at the Royal Bank of Scotland group.

NatWest customer Ideal Mats, based at Purdis Farm, supplies mats and other flooring and sells on the web.

But owner Jacqui Munn said it had been unable to do business, because of technical problems across RBS group brands, including NatWest, on Monday, and it had still not been resolved at noon on Tuesday.

She said: “It has been horrendous. It is then end of the month. We haven’t been able to pay our suppliers and I have had to phone them to explain why.

“Yet the chief of NatWest has been on Sky television today to say everything is OK and had been resolved. But it hasn’t.

“And I have spoken to my NatWest business advisor and they are not sure what is happening. It is the lack of information which is so frustrating.”

Customers could buy their products on-line, she said, but without access to their bank account they couldn’t check the arrival of the payments.

“We are an online business, and I am always in and out of my bank account. But I can’t check whether we have been paid, or make any payments to suppliers.

“I have other issues with NatWest. I think we will be leaving them now,” she added.

Royal Bank of Scotland boss Ross McEwan today admitted that it had failed to invest properly in systems for decades as he apologised for the embarrassing IT failure on the busiest online shopping day of the year.

The glitch left customers of RBS and its NatWest subsidiary unable to use credit and debit cards for three hours yesterday evening while the banks’ websites and smartphone apps were also affected.

Mr McEwan said: “For decades, RBS failed to invest properly in its systems. We need to put our customers’ needs at the centre of all we do. It will take time, but we are investing heavily in building IT systems our customers can rely on.

“I’m sorry for the inconvenience we caused our customers. We know we have to do better. I will be outlining plans in the New Year for making RBS the bank that our customers and the UK need it to be. This will include an outline of where we intend to invest for the future.”

In May, another glitch left RBS and NatWest customers using mobile apps unable to access their accounts online.

It followed a major fiasco in June last year which saw payments go awry, wages appear to go missing and home purchases and holidays interrupted, and cost the group £175 million in compensation.

The group’s then chief executive, Stephen Hester, announced that he would forgo his annual bonus at the time in the light of the problems. He was recently succeeded by Mr McEwan, who ran RBS’s retail arm from August 2012 to September 2013.

The new boss admitted last month that the bank still receives far too many complaints “often on issues that would never arise if our systems and processes were more effective”.