Santander has issued an urgent warning after a pensioner lost over £800 in a "highly believable" scam.
One pensioner was duped out of cash after receiving a call from a man posing as an employee at a mobile phone giant.
Scammers used a fraud tactic called social engineering that makes victims share personal information or perform actions that benefit the scammer without knowing.
Before realising that they've been scammed, it's often too late.
“This man had access to all of my account details and was able to tell me very precise details about the payments I was making,” the 73-year-old told Ayrshire Live.
"I would like to think that I ask a lot of questions and wouldn't fall for a scam, so this was very unsettling.
"When I became suspicious and eventually found out I had been scammed, I was angry that anyone could have access to such details in the first place.
"It is appalling that this type of person is out there and willing to try and profit from other people."
Santander has now warned its customers to remain vigilant when handing over personal details.
“Criminals use sophisticated techniques, invoking fear, panic or building a friendship," the bank warned.
These manipulative techniques are aimed to make the victim do something they wouldn’t normally take action on, including sending a payment without verifying the account, allowing the scammer access to their devices, or giving personal or security information.
The victim, who asked to remain anonymous, said she was asked to download an app on her phone.
This allowed her scammer to gain access to her private and confidential information.
Santander warn there has been a rise phone call and email scams pretending to be from banks or other financial bodies, advising people that their accounts have been compromised.
This is often called a safe account scam, the Express reports.
The calls then request an immediate transfer of funds into an account the scammer provides.
These scams often see the fraudster impersonate official organisations and persuade victims to give them remote control of their personal computer.
Santander added: "They do this by asking you to download a legitimate app such as TeamViewer or AnyDesk, or by simply getting you to click on a link.
“You should never allow remote access to your devices unless you have verified that the caller is genuine and trusted.”
Santander notes if a victim happens to grant access to the scammer they should never open banking apps or windows because remote access provides the scammer with full view and access to a person's computer screen.
Fraudsters also utilise emails, text or phone calls as part of "social engineering" scams.
“Never reply or act on anything without verifying that it’s from a legitimate source," Santander warns.
And in some cases banks may not be able to refund a victims’ lost money if they did not take necessary precautions to avoid becoming a victim in the first place.
Those who believe they may have fallen victim to a scam are urged to contact their bank or building society as soon as possible and report it to Action Fraud here.
