Feyenoord are said to be pursuing the matter, with FIFA and the Welsh FA involved. Cardiff have been making good their debts since the summer when TG and Vincent Tan invested more more into the club.
Feyenoord's anger is little calmer than Motherwell whose ranting chairman made a spectacle on Sky Sports on the day City signed Craig Bellamy. It worked. Motherwell were paid up with 10 days or so.
A City spokesman said: 'We have agreement on a payment plan with Feyenoord and we are working to pay off our historical debts.'