It does not take a large amount of unpaid debt to be black-listed, it could be a ridiculous amount even an unpaid unjustified charge
to be included in what they call list of “morosos”, although normally you should be advised when you are included in such a list. If in doubt you can check the registers, demand correction or even deletion.
Under artícle 29 of "Ley Orgánica 15/1999", of 13th december for the Protection of personal data Creditors one can register information about clients with unpaid debts, but the debt must exceed the unpaid accumulation of 4 months If you are on one of these lists, banks can refuse to offer credit and mortgages and some suppliers like electricity or telephone can insist on deposited funds before supplying. It can also affect your ability to buy anything on instalments.
There are several registers of “morosos” but the most used by financial institutions are ASNEF (Asociación Nacional de Entidades de Financiación) and RAI (Registro de Aceptaciones Impagadas), the latter also includes corporative bad debts.
To consult the ASNEF register you can ask for information by letter to the Servicio de Atención al Consumidor, byl fax to 91 768 77 53, by email to firstname.lastname@example.org or to apartado de correos 10.546, Madrid 28080. You must give your name or company name with DNI/CIF together with a reply address and your signature with copy of a bill in your name.
To consult RAI, you can simply visit their web page, quote your CIF and fill in the required form. To be able to consult them you need to register with them.
Of course, if you have a debt it should be paid, however if the register shows a debt that has been paid (creditors usually do not inform payments received) you are entitled to demand the removal from the list or have the information corrected if wrong. The registers must respond within 10 days and if you do not agree with the response you should place a complaint with the Agencia Española de Protección de Datos (AEPD) with copies of all relevant documents.
For further assistance in such matters you may consult Limit Consulting