Read your final response letter very carefully. You will often find that the complaint which is described in the final response is not really the complaint you are making. The complaints people who work for your bank or other institution have a knack of skewing your complaint so that it seems less reasonable than it really is – and then providing a refusal to you on the basis of the interpretation they have given to your problem.
The problem is that if you allow a distorted final response to be used as the basis for your complaint to the ombudsman, then your complaint will not be properly investigated because the ombudsman will not understand the real issue that you are unhappy with.
This happens so often that one can only believe that the banks and other institutions do this deliberately in order to give themselves a better chance of avoiding a decision against them.
Read your final response letter carefully and if you disagree in any way with it then write immediately to the bank and say that you disagree and say why you disagree and explain to them that they have misinterpreted your complaint or have ignored certain essential elements of your complaint. It may be that the bank will reject this and they will say that they have correctly interpreted your complaint but at least you have a paper trail and you can then put it before the ombudsman and include in your ombudsman complaint the fact that the bank have refused to investigate your complaint correctly.