In addition to its comprehensive regulatory responsibilities, the CBB very much remains of course a central bank, responsible for systemic stability (including oversight of the payments system  BIS Review 53/2007  1  and monetary policy), as well as for other central bank functions such as currency issue, reserves management and the provision of banking services to government.
Buyers can demand that the seller or another party that makes representations repurchase the mortgages if defects are found in the underlying loan documentation or in the underwriting that conflict with the sale agreements.