Just called again [they never called nor replied through email although they promised] to ask about the counteroffer I proposed and it was informed that it was not accepted.
They are currently just sticking to their 3 options proposed earlier. I will call back and discuss on further options.
ps: was just checking how much their e-vouchers would bring me on inter-island flights, and sadly, the 600 USD offer is quite pathetic, not even able to visit all the islands
and that is in coach!
Cheers!