FC Utrecht have reported Swansea City to FIFA for their failure to pay a sell-on clause that they are supposedly owed following Michel Vorm's move to Tottenham Hotspur.
Spurs signed the goalkeeper earlier this summer and his former Dutch employers claim that they are entitled to 30% of the fee that Swansea received, as part of the agreement that took Vorm to Wales in 2011.
Liberty Stadium chairman Huw Jenkins has allegedly told Utrecht that there is no fee to pay because they let Vorm go "for free", but their general manager Wilco van Schaik finds that hard to believe considering the 30-year-old's credentials.
"That's unbelievable and unacceptable," Van Schaik told BBC Wales, before confirming that they have referred the issue to FIFA.
"Michel is a very reliable goalkeeper in the Premier League. He is 30 years old, in the prime of his life. He still had a two-year contract and has a good reputation.
"Besides that, he's a solid member of the Dutch squad. We want to have the 30% as we agreed."
Vorm made 107 appearances for Swansea in all competitions between August 2011 and May 2014.