Spanish telecommunications company Telefónica resisted Millicom’s efforts to set aside a state court ruling holding it liable for abandoning its $623 million purchase of Telefonica’s Costa Rican business after a New York appeals court ruled Millicom couldn’t use a regulatory issue to spike the deal.

The Supreme Court of New York, Appellate Division, First Department, ruled that an agreement for Millicom International Cellular S.A. and Millicom Spain S.L. to purchase Telefónica S.A.’s Costa Rican unit wasn’t conditioned on obtaining the Costa Rican comptroller’s “autorización”, as that approval wasn’t necessary for the purchase to move forward. Because that approval wasn’t required, Millicom couldn’t use the missing authorization to walk away from the deal, the appeals court said on Tuesday.

“Because obtaining an autorización from the Comptroller was not legally required or permitted in Costa Rica—indeed, issuing autorizacións is not something the Comptroller does—it naturally follows that obtaining an Authorization was not an enforceable condition precedent to closing,” an appeals panel said.