If you have the paperwork that disproves their case it it fairly simple:
Dear ombudsman: the bank has said document x shows “quote their exact wording only”, I received this document y from the bank that said “quote exact part that disproves the bank”. And do this for all the documents you have, don’t provide commentary or interpretation, just the facts. You could end or start with - I believe the bank provided misleading information - but don’t go on a rant.
Your posts are confusing, full of emotional outrage and your communications with the fspo should not be like that.