Mumtaz Ali, 47, gave a quote to a customer while he was contracted to Shropshire Home Improvements, was later released by the company, then took a call from a customer accepting the quote.
Instead of telling them he no longer worked for the company, he lied and took the customer's money himself.
Telford Magistrates Court heard on Thursday that when the customer phoned up the company expecting the job to be done, they had to take the financial hit and do the work themselves.
Ali was arrested after the company reported it, and pleaded guilty to one count of fraud by false representation.
The court heard a statement from a Ben Shaw, director of Shropshire Home Improvements, who said that the company hired Ali in August of 2021.
Ali ceased working with the company towards the end of September, Mr Shaw said in his statement.
"Then, on December 7 of 2021 we got contacted by a [company] saying that they were expecting us to start work with them.
"We knew Mr Ali had visited them but as far as we knew the matter had [not] progressed.
"There was a quote given for £3,480, and an initial deposit of £1,500.
"Mr Ali had visited them on September 23 and they were unaware that he no longer worked with us.
"They gave him a deposit for £1,500 which was put into his personal account.
"They had heard nothing since. Realising what Mr Ali had done and desperate to maintain our reputation, we honoured the [work] and took the financial hit."
Ali, of Charolais Crescent in Lightwood, Stoke-on-Trent, pocketed £2,700 towards the 'work', although he paid £800 back soon after the deception was discovered.
In his statement, Mr Shaw said that £1,900 of the money is still outstanding.
"I'm out of pocket for £1,900. I can ill afford to pay this in the current climate."
Representing Ali in court, Mr Pat Kelly said that he first approached the customer as a legitimate employee of the company, after which they went away to consider the quote he gave.
When they then called him back after he had been released by the company and said they were ready to send the money, he "very stupidly" took the money for himself.
"Mr Ali was a... salesman, effectively a door-knocker - following up leads.
"He made the approach to the customer when he was employed by the company. It was a legitimate approach, it was an honest approach."
The magistrates, chaired by Alan Boyd, handed down a conditional discharge and ordered Ali to repay the outstanding £1,900, as well as £400 towards the cost of the prosecution and a £22 victim surcharge.