The war of words has been escalating for days, as the two sides traded charges and countercharges. Kraft claims that Starbucks unilaterally decided to end their agreement, and Starbucks says that Kraft failed to aggressively promote its brands, which include Seattle’s Best Coffee, in stores. The bitterness has also spilled into the fast-growing market for single-serve coffee machines, with Kraft accusing Starbucks of undermining sales of its Tassimo coffee system ahead of the peak holiday season.