National Australia Bank has entered some tricky terrain after deciding to withdraw two of its most successful loan products from the broker market.Thousands of NAB customers have been notified in the last month that the bank will no longer sell and service its Homeplus-branded mortgage.NAB has also pulled a line of credit product, known as the Peak Performance loan.The bank has given borrowers holding either product until the end of September to take up other "similar" credit products marketed by NAB. The total number of NAB customers affected is believed to be in the tens of thousands.Homeplus and Peak Performance were only sold through brokers, who have been asked by the bank to help manage the process of migrating customers to alternative products.In a memo sent to brokers last month, NAB said, "existing customer accounts are now beginning to change to NAB products with similar features".According to a NAB spokesman the migration process has proceeded so far with few complaints from customers."We have communicated directly to customers and brokers about the migration," the spokesman said."Feedback to the changes has been minimal."The main replacement product for customers on a Homeplus package is the bank's Tailored Home Loan package.NAB's decision to place borrowers in new products is unusual in the banking industry.The standard practice is to establish a run-off book for withdrawn loan products and to service existing customers until they pay out their loans.The challenge that lies ahead for NAB is one of meeting borrowers' expectations: packaged Homeplus borrowers have historically enjoyed lower rates than Tailored Home Loan customers. If that price differential is not maintained over time the bank risks disappointing many thousands of borrowers.Several brokers told Banking Day that many Homeplus borrowers were sceptical about the changes. Sheyne Walsh, the managing director of Sydney-based brokerage Kingsbridge Private, said the timing of the product migration had compounded the workload of brokers, which was already onerous given the wave of repricings and product amendments triggered by the regulatory crackdown on investment lending."Some clients are seething," said Walsh."Clients don't know how to handle it and it's creating a lot more work for brokers."The Homeplus mortgage was one of the most popular products sold through brokers because it carried lower fees and interest rates compared to most of NAB's range of proprietary mortgage products, including the Tailored Home Loan package."Homeplus was a standard variable rate-style of product which offered offset and redraw features," said Walsh."There was also tiering on pricing which delivered up to seventy basis points lower than the average loan."Homeplus consistently won the highest ratings from financial products research firms.In 2015, Canstar gave the Homeplus variable rate loan package the highest possible rating of five stars, while the Tailored HL Choice package fetched only four stars.Canstar also found there have been significant differences on fees paid on both products - with Homeplus levying a monthly fee of A$10 while borrowers on a Tailored HL Choice package were paying an annual fee of $395.Brokers told Banking Day they were concerned that the