*Energy provider npower says its representatives 'complied with strict guidelines' during incident
Flatmates Matthew Swale and Melanie Cunningham were terrified when they woke early one morning to discover a hoodie-wearing gang armed with crowbars hammering on their front door and shouting obscenities.
And the couple were even more distraught after the unknown intruders sprayed chemicals through their letterbox in a bid to subdue Matthew's anxious labrador.
But their fear has now been replaced by anger after it was revealed that the 7am raid last month was carried out by authorised bailiffs sent to sort out an unpaid gas bill - which had been left by a former tenant.
Terrified: Matthew Swale and his labrador Jake were the unfortunate victims of an early-morning raid by npower bailiffs
And now Matthew and Melanie are demanding compensation from energy supplier npower after having to pay hundreds of pounds in vet and repair bills.
Market trader Matthew, 28, and Melanie, 29, moved into the Grimsby railway cottage at the beginning of September and insist that they and their landlady contacted npower to inform them of the new tenancy.
But six weeks later, the company sent in the bailiffs because the previous tenant had still not paid bills totalling £980. The bailiffs were instructed to rip out the gas meter and replace it with a pre-pay one.
'I looked out of the window and saw a group of men wearing scruffy hoodies and tracksuit bottoms who had driven up in a pick-up truck,' Matthew told the Sunday Mirror.
'The man in charge was shouting, "It will make your life a lot easier if you answer the f***ing door".
'I thought they looked dangerous. They were kicking my front door and trying to open it with a crowbar. My flatmate was in tears.'
Matthew said he called the police rather than open the door because the gang - some of whom were sitting on the bonnet of his car - refused to reveal their identities.
Missing the target: Although bailiffs had the correct address, they did not realise that the tenant who owed npower money had moved out of the property almost two months earlier
After failing to gain access, the bailiffs shot chemical spray into the eyes of Matthew's labrador, Jake, before breaking in through a back door.
Matthew was eventually able to convince them they had targeted the wrong man by producing his driving licence and his tenancy agreement.
He claims his dog needed £350 worth of veterinary treatment and he has also had to pay out an additional £400 to get his doors repaired.
'Jake is the most placid dog you could imagine,' Matthew said.
'When they sprayed him, he just collapsed on the floor. he was throwing up and his eyes were watering. I thought he was going to die.
'Since this happened I have telephoned npower dozens of times but nothing has been done.'
Last month regulator Ofgem hit npower with a £2million fine for its sloppy customer service.
An npower spokesman told MailOnline that a trained dog handler had used the spray because 'the dog was still being aggressive and we were unable to gain access' - but insisted it was harmless and had no long-term effects.
The spokesman acknowledged that a door lock had been drilled out but that 'both the dog and the door were inspected prior to leaving by both the police and the agent and were deemed to be fine'.
And the company denied that Matthew had made contact to tell them he was a new tenant.
'We cannot stress enough the importance of letting your energy supplier know as soon as you move in to make sure you're not picking up the previous tenant's bills,' the spokesman said.
'We will only ever visit a property under these circumstances when all other options have been exhausted - and all personnel on site adhere to strict guidelines and we feel they were fully complied with in this instance.
'We would be more than happy to check any vet bills the owners says he has had to bear.'