Not half your deposit, all your deposit.
The clause is extremely abusive, to say the least, to keep 30% of the purchase price.
Normally in an off-plan purchase there are three steps:
1. You pay a non-refundable deposit (normally 6.000 euros).
2. You sign a private contract a month later with a downpayment of 20-30% of the purchase price.
3. You complete at the notaries two or three years later paying the remainding 70-80%.
If you pull-out of a contract before completion because you cannot find a buyer to your property and don’t want to take on a mortgage, you normally lose the deposit and half of the private contract’s downpayment (that is half of 20-30%= 10 or 15%).
So all in all you lose 10-15% of the purchase price plus the 6k deposit. This is rightful because If everyone did this the economical viability of every development would be at jeopardy because of the uncertainty of clients pulling out at will.
However, this is a far cry from losing 30% as your lawyers have done.
A verbal mandate is when the lawyer is acting as a verbal proxy. It’s only valid when you confirm later on what your lawyer has done in your behalf.
So If you haven’t granted a power of attorney, If I were you I would avoid avoid/refuse paying. If you haven’t signed that contract personally nor have you granted a power of attorney then you are not legally binded to the contract.
Seek advice with another unbiassed law firm asap. PM Mark, the forum administrator, for reliable law firms/lawyers.