First of all, the bank guarantee is part of your contract and the developers not supplying you with one are acting against the law. They can face serious penalties if you take it to court and criminal charges. (see Art 6 of Ley 57/1968, 27 de JULIO).
Second, your lawyer will most certainly not be inclined to answer your calls. What is there to answer? If I were you I would jump on the plane and appear in his office first thing Monday morning.
Say to him/her that unless he refunds you all fees you are heading straight to the Colegio of Abogados and the police!
Follow the same with MVG & Eralia. Threaten them that you will sue them and that you will also go to the police.
But in my opinion you will also need the assistance of a good litigation lawyer.
Anyway, the way things are going in Marbella, I am sure that these characters will not want to be in the visiting list of the Police!!!!