"I do not imagine his business would have called him away just now, if he had not wished to avoid a certain gentleman here."

This part of his intelligence, though unheard by Lydia, was caught by Elizabeth, and as it assured her that Darcy was not less answerable for Wickham's absence than if her first surmise had been just, every feeling of displeasure against the former was so sharpened by immediate disappointment, that she could hardly reply with tolerable civility to the polite inquiries which he directly afterwards approached to make. Attention, forbearance, patience with Darcy, was injury to Wickham. She was resolved against any sort of conversation with him, and turned away with a degree of ill humour which she could not wholly surmount even in speaking to Mr. Bingley, whose blind partiality provoked her. (Chapter 18)

I think Darcy’s insult from the assembly ball on top of his general ill will towards everyone (he was above his company) had an impact on Lizzy. It colors her view of him but I have to place blame on Darcy too because he makes a bad first impression and never corrects it. I think Darcy would have to explain himself frankly before Lizzy would believe him above Wickham at the Netherfield ball—as far as she can tell Wickham can make friends and keep them too. She likes him very much. On top of believing Wickham’s story, Darcy is the reason Wickham did not attend the ball and she is very disappointed. So much so, at the beginning of the chapter she can barely be civil to Bingley because he is Darcy’s friend. Lizzy’s emotions are running high at the ball; I do not think a general contradiction without particulars would impact her opinion. ;D