The situation was so severe at the brokerage that last month the Financial Conduct Authority (FCA) forced it to contact customers admitting they may not have received suitable advice and offering redress.
FOS received 50 complaints about Altrincham-based The Mortgage Matters Partnership, the second highest number for a non-lender in the mortgage sector.
Mortgage complaints soar
Overall, mortgage and home finance complaints received by the FOS increased by 20% to 5,418 in the first six months of the year.
Bank of Scotland was the most complained about mortgage lender with 773 complaints – repeating its position from the second consecutive six months.
Santander (546), Barclays (492), NatWest (333) and HSBC (292) completed the top five in mortgage complaints received by the FOS in the first half of the year.
Connells (52) and broker firm The Mortgage Matters Partnership (50) were the most complained about non-lenders.
Countrywide (28 complaints), Openwork (16) and Sesame (12) were other non-lenders to feature in the list.
Kensington saw 44% of cases resolved in the customer’s favour.
This was followed by Elderbridge (37%), Connells (33%), NatWest (33%), Barclays (31%) and Royal Bank of Scotland (31%).
The average uphold rate for the whole of the mortgage and home finance sector was 24%.
All cases rise
Overall the ombudsman took on a total of 201,600 new cases in the first six months of this year.
This represents a 22% increase in complaint figures when compared to the last six months of 2017 – and reflects rises in every product sector including Payment Protection Insurance (PPI) and banking.
PPI continues to be the most complained about product with just over 105,000 complaints – making up over half of all complaints to the FOS.
Complaints about banking and credit increased by 44% to around 63,000, with consumer credit complaints up 80% to almost 29,500.
Complaints about general insurance and protection rose by 15% to 20,260, life and pensions cases increased by 17% to 3,764 while investment complaints rose by 14% to 3,357.
