Lincoln plan to report Peterborough to the Football League for an alleged illegal approach to Lee Frecklington.
Frecklington is one of three players who were confirmed as January targets for Peterborough, with The Posh also enquiring about Grimsby's Tom Newey and non-league ace Ricky Holmes.
However, they have been knocked back in their attempts to land midfielder Frecklington by Lincoln, who are planning to bring the incident to the attention of the Football League.
"I'm extremely disappointed in Peterborough. Their approach is not acceptable. It's diabolical. It shows a complete lack of respect not only towards Lincoln City, but also to the player," Imps chairman Steff Wright told the Lincolnshire Echo.
"I'm not happy about it and will also contact the Football League to see what can be done, because, in my opinion, this just isn't right."
Peterborough director of football Barry Fry has attempted to play down the incident, saying: "We made contact with Lincoln to see what the chances were about signing Lee.
"But they knocked us back - In fact, Steff was adamant that he wouldn't sell any of his players to us, unless we offered a million quid. So as far as I'm concerned the deal is dead."