Suma (local rates) the latest!

Those of you who have owned property before in Spain, or those of you who have been informed by a legal/sales rep, will be aware that on top of the wealth tax that non residents pay and the Community charge that all owners pay there is a third tax the local rates.
We have, on several occasions, tried to find out how much this will be for our two phases, when it will begin and how far back it will be claimed.
As is usual in Spain one question leads to a whole host of questions and we have never got an answer to the above.
It appears that to pay the local rates (Suma)we first need a certificate of habitation! Certificates of habitation need to be issued before we move in and before we can connect to the utilities - see what we mean .
Most of us have lived in our propeties for between one and three years and we are informed that the furthest back that suma can be claimed by the Town Hall is four years.
Please could owners note that this is not something that the Community of Owners or any of its officials have any power over. If you get a bill and you dispute it, then please consult your solicitor. We will of course keep you informed of the situation