Bankruptcy Law Questions? Ask a Bankruptcy Lawyer.
Debts incurred after a bankruptcy was filed are not discharged by the bankruptcy. However, if the property went back to the bank, then you were no longer the owner and therefore were not responsible for HOA dus.
It is possible that you may be obligated for the dues accummulated between the filing and the bank's retaking of the property. However, even this amount may be barred if the court finds the HOA dues should have ceased to be imposed on you after you filed bankruptcy.
My suggestion is to contact your bankruptcy attorney and discuss the matter in detail with him/her. Your attorney will be able to advise you based on the particulars of your case.
However, my opinion is that they may only be entitled to the fees between the filing and the bank's retaking of the house. However, these funds may be voidable as well.