These are basically your choices:-(posted 7301 days ago)1. Do nothing - what will eventutally happen is that they will take you to court where you can obviously bring up any complaints you have about the amount they are claiming.
2. Offer them an increasing amount until they accept it - they are unlikely to accept this until after you have completed an income and expenditure form and they have checked that this is really all you can offer (after all, you could be a multi-millionaire for all they know).
3. Put yourself in bankruptcy - their claim will form part of the proceedings and subject to you having no assets or substantial income, after 1 year you will be discharged - you will then not owe them anything at all.
Your problem basically lies in the fact that the Halifax do not have to prove to you or anybody anything other than they obtained the best price as quickly as possible for the property. An offer to pay £30,000 in cash purchase is more likely to be accepted than £40,000 which needs to be raised by mortgage and the Halifax will no doubt be able to justify selling the property in such a manner and indeed, they would argue that such selling tactics were in your best interest as well to reduce the mortgage debt which even though you were repossessed, still carries on attracting interest and charges!