Joanna Stevens, who is having chemotherapy for secondary breast cancer, told me she was “over the moon” by NatWest’s u-turn after weeks of worry and stress.

You can read more about Joanna’s story and why NatWest wouldn’t initially refund her here.

But in a nutshell, scammers pretending to be from NatWest’s fraud unit tricked Joanna into using her card reader to stop money leaving her account. When she did, the fraudsters completely cleared out three of her accounts plus her overdrafts.

Joanna, who relocated from London to North Devon to reduce her debt and improve her financial situation, told me she had always thought she was savvy and switched on to cons like this.

“I did what they said out of fear,” she said. “It has really knocked my confidence.”

But Joanna was switched on. She didn’t meet the fraudsters’ demands without first asking the caller to verify they were a legitimate NatWest staff member.

Unfortunately for Joanna, the techniques used by scammers are becoming increasingly sophisticated.

The caller told Joanna to compare the phone number on the NatWest website with the number he had called her from. The criminals had used cloning technology, so the two numbers matched.

They were also able list off some of Joanna’s recent debit card activity such as a Tesco shop she’d done that week.  One expert told me it sounds like the fraudsters had cloned her computer.

Worryingly, Joanna’s story is not unique.

A spokesperson from UK Finance, the banking and finance trade body, told me: “Criminals are increasingly using phishing emails, text messages or phone calls in an attempt to trick people into giving away personal financial details.

“These scams are sophisticated and will often impersonate trusted organisations including banks, government agencies, utility companies which a large proportion of recipients are likely to use.”

So, how can you protect yourself?

The simplest thing to do is hang up the phone.

A bank will never call you out of the blue to ask for your PIN, password or to move money to another account. So put down the phone and if you’re worried, call your bank on a trusted number or visit your branch.

Joanna Faith is editor of YourMoney.com