A. First of all, it is important to highlight the issue of community charges. It takes a minimum effort to check whether the seller of the property has complied diligently with his obligations towards the community. Either the Administrator or the President of the community will issue a certificate stating that the community charges have been paid up to date. Any competent lawyer will ensure this matter is not overlooked.
The Community of owners has a preferential credit over any other creditor for the unpaid general expenses attributable to the calendar year when the transfer took place plus the preceding year. This preferential credit is achieved by a real attachment of the property transferred, which means that no matter how long the list of creditors pursuing a claim against the property is, the Community shall always have preference. As for the debts corresponding to the years previous to the preceding year, you will not be answerable. The seller will have to be sued by the Community in order to recover those amounts, and the neither the property nor yourself will have any obligation to satisfy those debts.
Going back to your question, we recommend to pay those unpaid debts which fall in the limit of the two calendar years and then sue the seller. You can either claim the unpaid charges together with interests and damages if any, or pursue a rescission of contract, if you consider you would have not purchased the property had you known those unpaid expenses were pending, again together with damages.
Also, the seller might be liable of a criminal offence if he swore in the Public deed of conveyance that all expenses were paid up to date, not being the truth.
Your remedy will depend on the seller´s financial standing in Spain and moreover, on whether you can find him at all. Your lawyer will have to due some research on this before you go to court.