Many of the complaints we see involving mortgages have arisen because of a difference between how customers expect their mortgage to work, and how it works in practice. Most people who take out a mortgage have some idea how it operates. However, relatively few mortgage customers have much understanding of the technicalities. Without first asking their lender, for example, many mortgage customers would be unable to say in detail exactly what practical effects a change in their mortgage arrangements would bring about.

Because a mortgage loan is usually for a large amount of money, quite small changes can – over time – make a significant difference in money terms. So mortgage customers can sometimes end up with a very unwelcome surprise if they have not fully understood what the consequences of a change would be. This is even more likely to be the case for customers who are experiencing financial difficulty and have limited options.

We are sometimes disappointed that the mortgage lender did not make greater efforts to explain matters to their customer when a problem or query first arose.

Even where lenders do attempt to explain matters, we see cases where they have failed to address an important point – or have given the customer an explanation that was wrong. In a fair number of disputes it seems to us that more effective communication on the part of the lender might well have prevented the complaint from arising in the first place.

http://www.financial-ombudsman.org.uk/publications/ombudsman-news/70/70-mortgage-complaints.html