I guess it depends which "knowledgeable" PAOK reporters you listen to. Usually they are quite consistent with their news, like atm the word is Konstantelias wants to stay.
Last season I distinctly recall all the news being about Konstantelias halfway out the door, until Savvidis stepped in and changed his mind. Within that conversation was a promise of a new, more lucrative deal. I honestly never heard that PAOK was keen to sell him last season (doesn't make it not true of course).
PAOK in the offseason after winning the title, was stingy. Players didn't come over the haggling over a couple of hundred thousand Euros. Meite, Pelkas, Chatzidiakos/Wieteska, plus signing free agents Lovren and Colley to cover arguably our most important player from last season in Koulierakis. I therefore think it is more likely they promised him a new deal but since they had him locked in anyway, didn't do it to save $.
Whether they are trying to rewrite history now to save face is another matter.