I have long characterized the walk to Samos as like Middle Earth on a good day and it is one of the best stretches I have walked in Galicia.
However, I would not be surprised if replies were very slow from the monastery and I would not be surprised if they did not respond at all. Some years ago I discovered that many French and Spanish enterprises do not treat e-mail in the same manner as North Americans (for here Canadians share US practice). Having not heard from hotels about reservations, I would send them a second or third email before I got a response: one French innkeeper wrote back to tell me to stop sending email, as they had received the first one, thank you very much. A confirmation did not seem to have entered his mind. When I got to Toulouse, I mentioned this and he seemed perplexed at my question.
Perhaps the monks at Samos may have felt that, since the information was on the web, and since albergues don't take reservations, they need not worry about it. Perhaps they may feel that, since March 2016 is so far off, there is no urgency to it. Perhaps they might think that, given that there are not many pilgrims at that time of year, you should not worry about it.
If, when you arrive there, they have no rooms at the hospederia for couples or women (frequently the case in monasteries for men) and if the albergue looks a bit too cold, all is not lost. I have stayed at the Hotel Victoria and while I am not as down on it as others, the Veiga might be just fine, as well as the Pension Rural Domus Itineris, a bit before the monastery. A casa rural, Casa de Diaz, is 4km beyond Samos, and a 5euro taxi ride if you wish to head back in for services.
I must admit that, while I enjoyed the tour and the frescoes are quite striking, I did not enjoy the service I attended--- I am a big fan of vespers, but with only four monks (such was my experience) in the huge abbey church, I cannot say that I would write home to mother about it. However, this is very subjective and experiences will vary.