The Greek keeper had tried to extend his loan at Swansea until the end of the season. However, he got stuck in traffic due to the snow on Monday and did not arrive at the Ricoh Arena in time to make the 5pm deadline.
Swansea had hoped for dispensation that clubs like Arsenal had after both clubs wrote to the Football League but this was denied.
Loan regulations mean that Swansea cannot now take Dimi on loan again after having him for three months already and City will have to look elsewhere to loan him out.