A legal bid by the Conservative party association to bring a claim against its former member Mark Reckless and his agent Chris Irvine was held in secret after a journalist was barred from proceedings.
The Rochester and Strood Conservative Association claimed that expenditure on Reckless' campaign of more than £3,000 was approved shortly before he defected.
The bill is said to have been amassed on now-unusable campaign literature promoting his bid to retain the key seat for the Tories, which local party figures said was an "avoidable expense".
The association brought the case which was today listed at Medway County Court in Chatham, Kent, as Rochester and Strood Constituency v Reckless/Irvine.
But Tom Pugh, a journalist for the Press Association, was denied access to the hearing.
After the case, local Tory party association member Stuart Tranter said he and the deputy district judge did not think "it would be helpful or necessary" to have the Press present.
Mr Tranter said deputy district judge Alan Ashley struck out the association's claim in its present form based on a "technicality".
He added: "We didn't discuss the substance of the claim. There was no judgment on whether or not the actions were right or wrong, or anything of that sort.
"On this purely technical basis, we were denied the opportunity and we are bitterly disappointed that we do not have the opportunity to argue the case."
Rule 39.2 of the Civil Procedure Rules which governs the conduct of cases in civil courts, including small claims court, states the general rule is that a hearing is to be in public.
A Judicial Office spokesman said: "Deputy District Judge Ashley did not invite the press into this hearing as it was concerned with legal argument, not factual evidence. The claim was struck out, so will not be going any further."
On twitter, Mark Reckless described the legal action as "sour grapes".