Bent's switch to Villa was completed for an initial £18million three days after the striker put in a shock transfer request.
Sunderland boss Steve Bruce claimed Bent had been unsettled and Quinn has revealed he feared three weeks ago that the 26-year-old had his mind elsewhere.
But Villa issued a strongly-worded statement stressing that there had been no "inappropriate approach" to the player.
"We understand Sunderland Football Club's need to explain to their naturally-disappointed supporters why Darren Bent has been allowed to leave their club," read the statement.
"It is disappointing, however, that Sunderland should try to besmirch the reputation of the player and Aston Villa Football Club in the process. We wish to make clear that at no time did Aston Villa make an inappropriate approach to the player or unfairly compromise the business of Sunderland Football Club."
Source: PA
Source: PA