However, Openwork has had almost half (47%) of the complaints against it upheld by the ombudsman in the first six months of the year.
Of Sesame’s 100 complaints, 19% were upheld. On average 36% of complaints are upheld by FOS, though this ranges from 3%-79% on an individual business basis.
These figures are lower than the same period last year, when Sesame had 160 complaints against it, with nearly a quarter upheld. Last year Openwork had 80 complaints, with a lower level of 24% upheld.
While St James Place Wealth Management had 71 complaints overall, only four of these were mortgage related.
Meanwhile, the lender with the most mortgage and home finance-related complaints was Santander, with 746 cases, followed by Bank of Scotland with 602. Barclays had 482, Natwest had 347 and Nationwide 299.
Overall, FOS took on around 170,000 new cases in the first six months of this year. This is a 13% increase on the last six months of 2016, with rises in almost every product category.
Almost two thirds of complaints come from just ten businesses. PPI accounts for over half of all complaints at almost 90,000.
FOS chief executive Caroline Wayman (pictured) said: “We’ve seen more complaints about most types of financial products in the first half of 2017.
“The FCA has just launched its communications campaign, which highlights that consumers have until August 2019 to make a complaint about mis-sold PPI. While we still don’t know what impact this will have on our workload, today’s data shows that PPI complaints are already increasing.”