Scottish Power debt enforcers have been caught on camera breaking into a woman's flat seeking payment for debts she did not owe.
The woman was on holiday at the time and was not a Scottish Power customer.
Doorbell video footage shows two uniformed men tampering with locks before going into the flat and identifying themselves as Scottish Power representatives.
The energy firm has admitted the error, apologised and offered compensation.
It is the latest in a series of reports from BBC Scotland featuring allegations of heavy-handed measures by representatives of Scottish Power.
The UK energy regulator Ofgem has now opened discussions with Scottish Power following the claims.
The woman's father said his daughter was on holiday in the north of Scotland on 20 August when she received an alert from the video doorbell.
Donald Maciver, 60, said she saw there were two men at the door and she realised they were trying to break into the flat.
"She tried to engage with them through the intercom and they chose to ignore that, and then watched for a period of 43 seconds as two guys walked through the door," he said.
Mr Maciver said he drove from his home in St Andrews to the property in Glasgow to investigate.
"I got down there and walked into the flat and couldn't see anything," he said. "It was like nobody had been there, it was absolutely nothing there at all. If it hadn't been for the video footage, nobody would have known anyone had been in this flat.
"Yet two men were in this flat for 27 minutes, nobody can explain to me what they were doing in a two-bedroom flat for 27 minutes. They were supposed to be looking for gas meters - a gas meter that happens to be in the basement."
Mr Maciver later found a letter from a debt collection firm addressed to someone who did not live in the stairwell.
He said his daughter had reported the letters three times to Scottish Power but they kept sending written demands for unpaid money.
'Sincerely apologised'
Mr Maciver said he faced a "denial culture" at the energy firm when he tried to complain.
"Even though you're not the customer - never have been a customer - you are wrong, they are right," he said. "It's up to you to prove you don't owe them money as opposed to them proving to you that you do."
He eventually received a letter in which Scottish Power admitted the error after contacting the CEO's office.
It states: "I sincerely apologised that we had attended the wrong address and I confirmed that your daughter's property was supplied by SSE.
"In view of the upset caused, I offered your daughter £500 as a gesture of goodwill and advised you that we were continuing to investigate which flat we do supply, your daughters' details were removed from our system."
It follows the case of Irene Girvan, from Glasgow, who claimed the energy giant hounded her for a year over money she insists she did not owe.
The 64-year-old told BBC Scotland she was threatened with debt collectors and missed a Covid booster jab while waiting for enforcement officers she believed were coming to change her locks.
Scottish Power has apologised for distress caused to Ms Girvan and cleared the debt. Officials said there was "no excuse for our failures" in this case.
An Ofgem spokeswoman said: "We treat seriously all allegations of customers not being treated fairly, and take action where appropriate.
"We have contacted Scottish Power over their investigation into the allegations reported by the BBC.
"Debt management activities must be done in a fair and reasonable way at all times. Suppliers cannot extend unlimited credit to customers, but we will not tolerate sharp practice or aggressive debt collection."
On Friday, Scottish Power launched a probe after a whistleblower told the BBC that call handlers working on behalf of the energy giant were told to threaten customers with debt enforcement - even over mistaken bills.
The man, an employee of an outsourced company, works in a call centre in the west of Scotland dealing with people who call to query outstanding balances.
The employee, who says he wants to protect his identity over fears he will lose his job, said it was clear to see where errors had been made on an account.
He said: "It may be a wrong meter reading, they've not been billed correctly, they might not be responsible for it, or they're not a Scottish Power customer. However, until that's dealt with then it's going to stand, we're going pursue them for that debt.
A Scottish Power spokesman said: "Scottish Power does not have processes or is it our intention to pursue account holders who have not been customers of Scottish Power.
"Like every other energy company in the UK we will follow up any existing debt a Scottish Power customer owes after they have switched to another supplier.
"Your source's allegations on our debt management policies are all untrue."
Following the volume of people getting in touch with the BBC raising concerns, Scottish Power has asked people to email
Contactus@scottishpower.com with BBC Account Query in the title.
