Lewandowski recently said that he would sign a Bayern Munich deal in January before withdrawing his comments a day later, but Dortmund feel that the player's management have acted unprofessionally since the summer.
"Once again, this is one-sided, negative and biased reporting, paired with indiscretion from the agents' side," director of football Michael Zorc told Bild. "For me, that is very dubious."
Chief executive Aki Watzke was equally disappointed. He said: "I'm not surprised that this subject has been reopened. We will continue to avoid making any comments - doing so would be like having mustard after the meal."
Lewandowski said yesterday that he had been misquoted after the DFB Pokal win over 1860 Munich.