Can't agree with you acer.
Bits of paper with a bit of scribble on them for such a large amount of money suggests to me that something is not right and needs to be put right.
In any company if this was to happen there would be heads rolling (look at what is happening at Tesco right now)
size of the operation is irrelevant, if things are not right it needs sorting - especially in Spain where there is so much corruption between (some) administrators and (some) Presidents - it is very tempting - only this week I was offered money after a supplier did some work for the community (I refused), it goes on all the time.
Back to the OP, It is possible that the "contractor" in question did a "cash deal" and obviously no invoice or paperwork can be produced in case it is tracked back.
Or maybe the contractor is not a registered company and pays no tax to the goverment (I know at least One company that works like that, and have been doing so for many years. Nobody likes paying tax, but i do believe you have to put something into the system. I pay tax in Spain, because i use the health service and the Town Hall do their stuff like collecting my garbage ect, and i feel i want to put something back for those services - I know many that don't, they just "take"
I stand by my comments, but it can only really be done via the AGM. The OP has six months to gain support, put himself up for President and start to change things.
Just as a footnote. Three years ago (next week I will be entering my fourth) I became President of our community. We had no money and couldn't pay all our bills - that has changed.
The owners wanted to sack the gardener/handyman, I said "give me this year to sort him out and if i can't then we sack him" now my gardener/handyman is my most trusted person on site - he is my eyes & ears and everybody loves him - tha's called "man management"
I did the same to the Administrators, I gave them 12 months. It soon became obvious that things were not right, so at the next AGM i had them fired - much to their amazement.
Now we have what i believe to be one of the best administrators in our area (Calahonda), all the accounts are online and up to date evry day for me to view. I rarely need to speak to the "main man" unless i need advice or just a catch-up as to where we are. In other words "I run the community & he does the books and legal stuff" Only once have i had to remind a member of his staff that "you work for me, not the other way round, that's how it should be, and i work for the owners.
I see our bank account (and check it every day) so i know where the money is going, incedently our administrator, never takes an invoice without IVA on it, unless it is for a small job such as paying for "pool cleaning when our man is on holiday.
Three years later we have money in the bank, we have spent 75,000 euro on improvements this year to satisfy the Town Halls "health & safety" issues around swimming pools, many urbanisations on the Costa del Sol have had their pools closed by the Town Hall because they have no money to bring their "Urbanisation health & safety" issues up to date.
So nobody will tell me "it can't be done" and to generate paperwork explaining the problems, yes sometimes it is nesessary to keep records for owners to see but sometimes you need to just "kick peoples backside" (towards the exit door).
And just for the record I did used to run a company in the UK.
Rant over.