The back-and-forth battle between the card associations and retailers who accuse them of rate-fixing is beginning to look like a tennis match — with a score that's anything but "love all."

Last summer, it appeared that card companies and retailers had reached a truce in the anti-trust battle. But by September, a disgruntled National Retail Federation board decided to take legal steps to block the settlement. And when a judge granted preliminary approval to the settlement in November, merchants filed an appeal to the ruling.

Along the way, the biggest players on the retail side, including Walmart and Target, availed themselves of the option to back out of the settlement by May 28 — as did more than 7,000 other signatories to the original complaint.

Even before the deadline, dropouts Target, Macy's, Kohl's, Staples, JC Penney, Office Depot and 11 other major brands filed a new anti-trust lawsuit against Visa and MasterCard. Walmart did not join the new filing, but was believed to be planning to bring its own action, said a report from Bloomberg.

So, in a preemptive move that Visa CEO Charlie Scharf said was designed to "protect its interests," the card company this week filed a suit against Walmart to stop the retail giant's presumed filing.

In a statement, Scharf said, "We remain committed to engaging with Walmart and all merchants to resolve our differences amicably, while seeking new ways to work with our merchant partners and support our mutual growth objectives."

Walmart issued its own statement through spokesman Randy Hargrove, who said, "We are disappointed that Visa chose to file this unwarranted and unsupportable lawsuit in retaliation for our decision to opt out and object to an unfair settlement agreement."

It seems clear that for this contest, "match point" is still some years away.

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