The European Commission is taking Ireland to court for failing to recover taxes from Apple.

The executive arm of the EU ordered Ireland last year to recover 13 billion euros ($15.28 billion) back from Apple after it said the U.S. multinational firm benefited from sweetheart tax deals.

“Ireland has to recover up to 13 billion euros in illegal state aid from Apple. However, more than one year after the Commission adopted this decision, Ireland has still not recovered the money, also not in part,” Margrethe Vestager, the EU’s commissioner for competition, said in a statement Wednesday.

“We of course understand that recovery in certain cases may be more complex than in others, and we are always ready to assist. But member states need to make sufficient progress to restore competition. That is why we have today decided to refer Ireland to the EU Court for failing to implement our decision,” Vestager added.

Brussels opened an investigation in 2014 into tax arrangements between Ireland and Apple. Last year, the Commission concluded that Ireland had issued two tax rulings that “substantially and artificially lowered the tax paid by Apple in Ireland since 1991.”

The Irish authorities have responded to the Commission’s decision to take them to court, saying they never agreed with its assessment in the first place.

“It is extremely regrettable that the Commission has taken this action, especially in relation to a case with such a large scale recovery amount. Ireland has made significant progress on this complex issue and is close to the establishment of an escrow fund, in compliance with all relevant Irish constitution and European Union law,” the Irish authorities said in a statement.

They added they have been in “constant contact” with the Commission and Apple on all aspects of this process.

The decision to take Ireland to the European court comes as the EU has asked Luxembourg to recover 250 million euros ($294 billion) from Amazon, also due to illegal tax arrangements.