A vet who was called by a fraudster pretending to be from TSB has told how she lost almost £17,000 in a matter of minutes, amid mounting concern that TSB customers are being targeted by conmen taking advantage of the bank's recent IT meltdown.

UPDATE Tuesday 22 May: Since we published this story, Rachel has now been told her money will be refunded in full.

Rachel, who lives in London but asked not to give her full name, told MoneySavingExpert she was horrified to see her account had been raided on Friday, after receiving a fake call apparently reporting suspicious activity on her account.

She says the caller appeared to know some of her personal details and told her he was calling because two direct debits had been set up her account. He insisted she give a verification code she had been sent via text message to freeze her account and protect herself from fraud.

TSB says it's investigating the case - but it's not yet clear if Rachel will get any of her money back. Rachel's story comes after MoneySavingExpert reported last week on a raft of complaints from TSB customers about suspected fraudulent activity on their accounts, with some seeing £1,000s taken.

Are you affected by TSB's recent issues? See our TSB online banking problems guide for full help.

'I feel quite foolish - but this was sophisticated'

Rachel, who says she was one of those locked out of her account when TSB first experienced online banking problems, says she received a call out of the blue on Friday by someone claiming to be from TSB. Rachel says the caller, who had a Birmingham accent, appeared to know Rachel's name, address, phone number and account number, and he said he was calling because he could see two direct debits had been set up on her account.

Rachel said: "I told him I wouldn't give any personal details, but he said not to worry he wouldn't ask for any - I just needed to give a six digit verification code so my account could be shut down."

She received this code as a text message on her phone while speaking to the fraudster, and was persuaded to read it out to him. "Within 15 minutes they moved £17,000," she said.

After the call Rachel called TSB to verify the call, and says she spent more than 90 minutes initially trying to contact the bank's fraud department as she kept getting cut off. She also experienced long delays while trying to check progress on her case over the next couple of days - on one occasion she claims had to wait more than four hours - and went into branch as well.

Rachel has reported her case to TSB, Action Fraud, the Financial Ombudsman Service and the Financial Conduct Authority and says her next step will be to contact a lawyer.

She said: "My mum is a lawyer and my dad is a cop. I consider myself to be quite cynical and careful so I feel quite foolish - but this was sophisticated.

"Like my parents said, no-one has died, but I saved that for a really long time. I got some of the money doing night shifts and one time I worked 24 hours straight, so when I think how hard I worked for it, it's quite bad."

What does TSB say?

A TSB spokesperson said: "We're dedicated to protecting our customers' accounts and work really hard to make sure they don't become a victim of fraud. It is a sad fact that fraudsters might try to take advantage of situations like these. [Rachel's] case is very important to us and our team here are currently looking into this and we will be reaching out to her to put things right as quickly as possible. 

"We are reminding customers not to click on any links or messages which they receive that they feel are suspicious. We’d never ask for a PIN, password or full memorable information. If people are ever unsure, they should listen to their instincts and not be rushed, and contact us first to be sure."

We've asked TSB to confirm if it will refund all customers who've lost money to an authorised push payment scam following its IT meltdown, but it's yet to confirm it will do so - we'll update this story when we know more.