You are buying off-plan and the property is rustic ???!!!
Did your lawyer advise you to go on ahead ?
Being rustic land it is totally forbidden to build on it. You will probably never get that Licence of First Occupation.
Problem is that your lawyer (who recommended you that lawyer ?) should have advised you not to buy off-plan on rustic land. It will be very difficult for you to claim breach of contract because i’m sure the contract mentions it is rustic.
You will never get Bank Guarantees because no bank will do this on rustic land as it is completely illegal. You will get no guarantees on your stage payments, I’m sorry.
The Spanish Authorities as of late are going nuts on this issue due to the coming municpal (local) elections next year. Many majors are being imprisoned and denounced on planning corruption.
I recommend you to hire an independant lawyer in your area recommended by Mark (web administrator). And you better start thinking of going to the Bar College and denounce the lawyer you hired in the first place for not warning you on the very stupid thing you were doing on signing such a contract.