Perhaps it may help for you to post on the LEGAL page as there are a couple of Spanish Legal Beagles who are very helpful with this type of question,
My knowledge is limited, but I can relate my experiences,
There are various Associations/committes that I have seen in Spain
The Community association for urbanisation/ or just a block of apartments is use a self governing affair which comprises of the members of the define area, IE one Block of Apartments with shared facilities or maybe three or four blocks with shared facilities, there will usually be a meeting point wherein minutes etc are published for all to see. There is usually an elected president who looks after the day to day, interfaces with the council and takes care of any requests etc, then a meeting on a regular basis where the committee (I hate that word) work through the issues and requirements.
In Villages and small district type urbanisation(population mainly spanish) there is usually an association of neighbours (asociaci?n de los vecinos), which is run very much on the same lines, but in all the meetings i have been to you will need a very good understanding of Spanish, and as you say Chaos seems to be the order of the day, The Spanish are extremely vocal, passionate and loud about things they care about and are not frightened of stating and standing their ground!!!!!. Saying that ours seems to work well, over the last few years, we have had mains water connected, electricity upgraded, rubbish collection now FOC, and even the tracks around the village tarmaced (well done the Alcalde!!). This has not cost any of us a penny, so they do work, They are now working on a new plan for the urban area, with the aim of controlling the future development of the area, and have even managed to get the main road diverted around the village!!. They organise the Fiestas, local walks to enjoy the area, food and drink events, and last year we had the school used as hall for an international food festival (Ok sounds a bit grand), but the residents were invited to make and bring dishes from their own country/locality, it was a great day, but a lot was learnt about whats going, on, tasting different foods, (gaspacho YUK!!) and meeting new people to the area, !! all great fun.
We pay about 45? a year for expenses (Mostly wine and fireworks!!)
As Susan says above, it only works when the residents actively support the association and ensure they have a clear mandate to act on the communities behalf.
I’m not sure whether the associations have any rights legally, but I believe on the new urbos, they have to have a written charter which is part of the contract of sale, defining the rights and rules of the community!!.
Hope this helps, but please bear in mind this experience only, so you need to check on the facts etc,